This thesis explores the design of systems that can climb vertical surfaces with non-negligible d... more This thesis explores the design of systems that can climb vertical surfaces with non-negligible dynamics in the sagittal plane. The development of a low-dimensional model addresses a lack of understanding of sagittal-plane dynamics during climbing in the space of reduced-order dynamic models of legged systems. Using a construction derived from the well-known and well-studied Spring-Loaded Inverted Pendulum (SLIP), we propose a two-legged system with both torsional and linear compliance driven by a position-controlled rotational actuator. Two simple foot models are considered to explore their e↵ect on the dynamics and stability of the system. Results of the model indicate the existence of passively stable gaits during climbing as well as during inverted running and also suggest mechanical tuning parameters for physical climbing systems. A robotic platform capable of producing dynamic climbing behaviors is introduced. A reduced profile, sprawled posture, and improved internal mechanics allow the CLASH platform to be adapted to di↵erent climbing substrates. A passive claw engagement mechanism is proposed and tested with simulated steps to verify the design. With these mechanisms, CLASH becomes the first robotic platform capable of climbing loose cloth and climbs vertically at 15cm/s or 1.5 body-lengths per second. When climbing ferromagnetic surfaces, the system is capable of climbing at 1.8 body-lengths per second. To climb smooth, hard surfaces, a foot with a passively aligning ankle with a tendon-loaded gecko-inspired adhesive is designed and tested using simulated steps. With these engagement mechanisms, the system is able to climb at 1 body-length per second on acrylic with a 70 incline. A simple foot-impact model is created to explain the robot's inability to climb faster or up steeper inclines due to the sagittal-plane reaction forces created during rapid running. i To my two ladies, Alexis and Nina. And to any others that want to join our little clan.
A high-performance, lightweight prototype robotic leg using series-elastic actuation was develope... more A high-performance, lightweight prototype robotic leg using series-elastic actuation was developed in previous work to study the effects of series-elastic actuation in vertical jumping. However, there was also a desire to perform other high-speed dynamic motions with the leg such as cycling. To this end, the thesis goals were focused on improving the existing embedded controller as well as implementing a high-speed cycling function. An analog potentiometer was used to replace a faulty sensor at the knee joint, which houses the compliant element of the series-elastic actuator. Changes were made to the previous controller hardware and software in order to utilize the data available from this new sensor. Using several new functions, a smooth cyclical trajectory was created and followed by the robotic leg at high speeds. The entire cycle was completed in less than 0.5 seconds with a stroke of more than 15cm. These functions will open the path for development of precise trajectory control in future robotic legs, as well as allow for the study of series-elastic actuation through a new dynamic motion. The design of the aforementioned changes and functions are discussed. The significance of the thesis results is discussed, as well as the expected course of future work.
Abstract………………………………………………………………………………….....v Acknowledgments………………………………………………..……………..………...vi ... more Abstract………………………………………………………………………………….....v Acknowledgments………………………………………………..……………..………...vi List of Figures…………………………………….…………………..…..…………..…...vii
A high-performance, lightweight prototype robotic leg using series-elastic actuation was develope... more A high-performance, lightweight prototype robotic leg using series-elastic actuation was developed in previous work to study the effects of series-elastic actuation in vertical jumping. However, there was also a desire to perform other high-speed dynamic motions with the leg such as cycling. To this end, the thesis goals were focused on improving the existing embedded controller as well as implementing a high-speed cycling function. An analog potentiometer was used to replace a faulty sensor at the knee joint, which houses the compliant element of the series-elastic actuator. Changes were made to the previous controller hardware and software in order to utilize the data available from this new sensor. Using several new functions, a smooth cyclical trajectory was created and followed by the robotic leg at high speeds. The entire cycle was completed in less than 0.5 seconds with a stroke of more than 15cm. These functions will open the path for development of precise trajectory control in future robotic legs, as well as allow for the study of series-elastic actuation through a new dynamic motion. The design of the aforementioned changes and functions are discussed. The significance of the thesis results is discussed, as well as the expected course of future work.
This thesis explores the design of systems that can climb vertical surfaces with non-negligible d... more This thesis explores the design of systems that can climb vertical surfaces with non-negligible dynamics in the sagittal plane. The development of a low-dimensional model addresses a lack of understanding of sagittal-plane dynamics during climbing in the space of reduced-order dynamic models of legged systems. Using a construction derived from the well-known and well-studied Spring-Loaded Inverted Pendulum (SLIP), we propose a two-legged system with both torsional and linear compliance driven by a position-controlled rotational actuator. Two simple foot models are considered to explore their e↵ect on the dynamics and stability of the system. Results of the model indicate the existence of passively stable gaits during climbing as well as during inverted running and also suggest mechanical tuning parameters for physical climbing systems. A robotic platform capable of producing dynamic climbing behaviors is introduced. A reduced profile, sprawled posture, and improved internal mechanics allow the CLASH platform to be adapted to di↵erent climbing substrates. A passive claw engagement mechanism is proposed and tested with simulated steps to verify the design. With these mechanisms, CLASH becomes the first robotic platform capable of climbing loose cloth and climbs vertically at 15cm/s or 1.5 body-lengths per second. When climbing ferromagnetic surfaces, the system is capable of climbing at 1.8 body-lengths per second. To climb smooth, hard surfaces, a foot with a passively aligning ankle with a tendon-loaded gecko-inspired adhesive is designed and tested using simulated steps. With these engagement mechanisms, the system is able to climb at 1 body-length per second on acrylic with a 70 incline. A simple foot-impact model is created to explain the robot's inability to climb faster or up steeper inclines due to the sagittal-plane reaction forces created during rapid running. i To my two ladies, Alexis and Nina. And to any others that want to join our little clan.
Exceptional performance is often considered to be elegant and free of 'errors' or misstep... more Exceptional performance is often considered to be elegant and free of 'errors' or missteps. During the most extreme escape behaviours, neural control can approach or exceed its operating limits in response time and bandwidth. Here we show that small, rapid running cockroaches with robust exoskeletons select head-on collisions with obstacles to maintain the fastest escape speeds possible to transition up a vertical wall. Instead of avoidance, animals use their passive body shape and compliance to negotiate challenging environments. Cockroaches running at over 1 m or 50 body lengths per second transition from the floor to a vertical wall within 75 ms by using their head like an automobile bumper, mechanically mediating the manoeuvre. Inspired by the animal's behaviour, we demonstrate a passive, high-speed, mechanically mediated vertical transitions with a small, palm-sized legged robot. By creating a collision model for animal and human materials, we suggest a size depende...
FigS1_v1.ai from Transition by head-on collision: mechanically mediated manoeuvres in cockroaches and small robots
Exceptional performance is often considered to be elegant and free of 'errors' or misstep... more Exceptional performance is often considered to be elegant and free of 'errors' or missteps. During the most extreme escape behaviours, neural control can approach or exceed its operating limits in response time and bandwidth. Here we show that small, rapid running cockroaches with robust exoskeletons select head-on collisions with obstacles to maintain the fastest escape speeds possible to transition up a vertical wall. Instead of avoidance, animals use their passive body shape and compliance to negotiate challenging environments. Cockroaches running at over 1 m or 50 body lengths per second transition from the floor to a vertical wall within 75 ms by using their head like an automobile bumper, mechanically mediating the manoeuvre. Inspired by the animal's behaviour, we demonstrate a passive, high-speed, mechanically mediated vertical transitions with a small, palm-sized legged robot. By creating a collision model for animal and human materials, we suggest a size depende...
S3_video_T_480p.mov from Transition by head-on collision: mechanically mediated manoeuvres in cockroaches and small robots
Exceptional performance is often considered to be elegant and free of 'errors' or misstep... more Exceptional performance is often considered to be elegant and free of 'errors' or missteps. During the most extreme escape behaviours, neural control can approach or exceed its operating limits in response time and bandwidth. Here we show that small, rapid running cockroaches with robust exoskeletons select head-on collisions with obstacles to maintain the fastest escape speeds possible to transition up a vertical wall. Instead of avoidance, animals use their passive body shape and compliance to negotiate challenging environments. Cockroaches running at over 1 m or 50 body lengths per second transition from the floor to a vertical wall within 75 ms by using their head like an automobile bumper, mechanically mediating the manoeuvre. Inspired by the animal's behaviour, we demonstrate a passive, high-speed, mechanically mediated vertical transitions with a small, palm-sized legged robot. By creating a collision model for animal and human materials, we suggest a size depende...
S2_video_T_720p.mov from Transition by head-on collision: mechanically mediated manoeuvres in cockroaches and small robots
Exceptional performance is often considered to be elegant and free of 'errors' or misstep... more Exceptional performance is often considered to be elegant and free of 'errors' or missteps. During the most extreme escape behaviours, neural control can approach or exceed its operating limits in response time and bandwidth. Here we show that small, rapid running cockroaches with robust exoskeletons select head-on collisions with obstacles to maintain the fastest escape speeds possible to transition up a vertical wall. Instead of avoidance, animals use their passive body shape and compliance to negotiate challenging environments. Cockroaches running at over 1 m or 50 body lengths per second transition from the floor to a vertical wall within 75 ms by using their head like an automobile bumper, mechanically mediating the manoeuvre. Inspired by the animal's behaviour, we demonstrate a passive, high-speed, mechanically mediated vertical transitions with a small, palm-sized legged robot. By creating a collision model for animal and human materials, we suggest a size depende...
Exceptional performance is often considered to be elegant and free of 'errors' or misstep... more Exceptional performance is often considered to be elegant and free of 'errors' or missteps. During the most extreme escape behaviours, neural control can approach or exceed its operating limits in response time and bandwidth. Here we show that small, rapid running cockroaches with robust exoskeletons select head-on collisions with obstacles to maintain the fastest escape speeds possible to transition up a vertical wall. Instead of avoidance, animals use their passive body shape and compliance to negotiate challenging environments. Cockroaches running at over 1 m or 50 body lengths per second transition from the floor to a vertical wall within 75 ms by using their head like an automobile bumper, mechanically mediating the manoeuvre. Inspired by the animal's behaviour, we demonstrate a passive, high-speed, mechanically mediated vertical transitions with a small, palm-sized legged robot. By creating a collision model for animal and human materials, we suggest a size depende...
Supplementary material from "Transition by head-on collision: mechanically mediated manoeuvres in cockroaches and small robots
Exceptional performance is often considered to be elegant and free of 'errors' or misstep... more Exceptional performance is often considered to be elegant and free of 'errors' or missteps. During the most extreme escape behaviours, neural control can approach or exceed its operating limits in response time and bandwidth. Here we show that small, rapid running cockroaches with robust exoskeletons select head-on collisions with obstacles to maintain the fastest escape speeds possible to transition up a vertical wall. Instead of avoidance, animals use their passive body shape and compliance to negotiate challenging environments. Cockroaches running at over 1 m or 50 body lengths per second transition from the floor to a vertical wall within 75 ms by using their head like an automobile bumper, mechanically mediating the manoeuvre. Inspired by the animal's behaviour, we demonstrate a passive, high-speed, mechanically mediated vertical transitions with a small, palm-sized legged robot. By creating a collision model for animal and human materials, we suggest a size dependence favouring mechanical mediation below 1 kg that we term the 'Haldane limit'. Relying on the mechanical control offered by soft exoskeletons represents a paradigm shift for understanding the control of small animals and the next generation of running, climbing, and flying robots where the use of the body can off-load the demand for rapid sensing and actuation.
Exceptional performance is often considered to be elegant and free of ‘errors’ or missteps. Durin... more Exceptional performance is often considered to be elegant and free of ‘errors’ or missteps. During the most extreme escape behaviours, neural control can approach or exceed its operating limits in response time and bandwidth. Here we show that small, rapid running cockroaches with robust exoskeletons select head-on collisions with obstacles to maintain the fastest escape speeds possible to transition up a vertical wall. Instead of avoidance, animals use their passive body shape and compliance to negotiate challenging environments. Cockroaches running at over 1 m or 50 body lengths per second transition from the floor to a vertical wall within 75 ms by using their head like an automobile bumper, mechanically mediating the manoeuvre. Inspired by the animal's behaviour, we demonstrate a passive, high-speed, mechanically mediated vertical transitions with a small, palm-sized legged robot. By creating a collision model for animal and human materials, we suggest a size dependence favo...
We study the detailed locomotor mechanics of a small, lightweight robot (DynaRoACH, 10 cm, 25 g) ... more We study the detailed locomotor mechanics of a small, lightweight robot (DynaRoACH, 10 cm, 25 g) which can move on a granular substrate of closely packed 3 mm diameter glass particles at speeds up to 50 cm/s (5 body length/s), approaching the performance of small, highperforming, desert-dwelling lizards. To reveal how the robot achieves this high performance, we used high speed imaging to capture kinematics, and developed a numerical multi-body simulation of the robot coupled to an experimentally validated discrete element method (DEM) simulation of the granular media. Average forward speeds measured in both experiment and simulation agreed well, and increased non-linearly with stride frequency, reflecting a change in the mode of propulsion. At low frequencies, the robot used a quasi-static "rotary walking" mode, in which the granular material yielded as the legs penetrated and then solidified once vertical force balance was achieved. At high frequencies, duty factor decreased below 0.5 and aerial phases occurred. The propulsion mechanism was qualitatively different: the robot ran rapidly by utilizing the speed-dependent fluid-like inertial response of the material. We also used our simulation tool to vary substrate parameters that were inconvenient to vary in experiment (e.g., granular particle friction) to test performance and reveal limits of stability of the robot. Using small robots as physical models, our study reveals a mechanism by which small animals can achieve high performance on granular substrates, which in return advances the design and control of small robots in deformable terrains.
Micro- and Nanotechnology Sensors, Systems, and Applications IV, 2012
Palm sized legged robots show promise for military and civilian applications, including explorati... more Palm sized legged robots show promise for military and civilian applications, including exploration of hazardous or difficult to reach places, search and rescue, espionage, and battlefield reconnaissance. However, they also face many technical obstacles, including-but not limited to-actuator performance, weight constraints, processing power, and power density. This paper presents an overview of several robots from the Biomimetic Millisystems Laboratory at UC Berkeley, including the OctoRoACH, a steerable, running legged robot capable of basic navigation and equipped with a camera and active tail; CLASH, a dynamic climbing robot; and BOLT, a hybrid crawling and flying robot. The paper also discusses, and presents some preliminary solutions to, the technical obstacles listed above plus issues such as robustness to unstructured environments, limited sensing and communication bandwidths, and system integration.
2012 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2012
A 10 cm hexapedal robot is adapted to dynamically climb near-vertical smooth surfaces. A gecko-in... more A 10 cm hexapedal robot is adapted to dynamically climb near-vertical smooth surfaces. A gecko-inspired adhesive is mounted with an elastomer tendon and polymer loop to a remote-center-of-motion ankle that allows rapid engagement with the surface and minimizes peeling moments on the adhesive. The maximum velocity possible while climbing decreases as the incline gets closer to vertical, with the robot able to achieve speeds of 10 cm second −1 at a 70-degree incline. A model is implemented to describe the effect of incline angle on climbing speed and, together with high-speed video evidence, reveals that climbing velocity is limited by robot dynamics and adhesive properties and not by power.
The International Journal of Robotics Research, 2013
We study the locomotor mechanics of a small, lightweight robot (DynaRoACH, 10 cm, 25 g) which can... more We study the locomotor mechanics of a small, lightweight robot (DynaRoACH, 10 cm, 25 g) which can move on a granular substrate of 3 mm diameter glass particles at speeds up to 5 body length/s, approaching the performance of certain desert-dwelling animals. To reveal how the robot achieves this performance, we used high-speed imaging to capture its kinematics, and developed a numerical multi-body simulation of the robot coupled to an experimentally validated simulation of the granular medium. Average speeds measured in experiment and simulation agreed well, and increased nonlinearly with stride frequency, reflecting a change in propulsion mode. At low frequencies, the robot used a quasi-static “rotary walking” mode, in which the substrate yielded as legs penetrated and then solidified once vertical force balance was achieved. At high frequencies the robot propelled itself using the speed-dependent fluid-like inertial response of the material. The simulation allows variation of parame...
S1_video_T_720p.mov from Transition by head-on collision: mechanically mediated manoeuvres in cockroaches and small robots
Exceptional performance is often considered to be elegant and free of 'errors' or misstep... more Exceptional performance is often considered to be elegant and free of 'errors' or missteps. During the most extreme escape behaviours, neural control can approach or exceed its operating limits in response time and bandwidth. Here we show that small, rapid running cockroaches with robust exoskeletons select head-on collisions with obstacles to maintain the fastest escape speeds possible to transition up a vertical wall. Instead of avoidance, animals use their passive body shape and compliance to negotiate challenging environments. Cockroaches running at over 1 m or 50 body lengths per second transition from the floor to a vertical wall within 75 ms by using their head like an automobile bumper, mechanically mediating the manoeuvre. Inspired by the animal's behaviour, we demonstrate a passive, high-speed, mechanically mediated vertical transitions with a small, palm-sized legged robot. By creating a collision model for animal and human materials, we suggest a size depende...
ABSTRACT We present an experimental and computer simulation study of a small, light-weight, biolo... more ABSTRACT We present an experimental and computer simulation study of a small, light-weight, biologically inspired robot running on a model granular medium (GM), 3 mm diameter glass particles. The six-legged RoACH robot (10 cm long, 25 grams) utilizes an alternating tripod gait to run at speeds up to 25 cm/sec. Forward speed increases with increasing limb frequency 0<f<12 Hz. An experimentally validated discrete element method (DEM) simulation of the device captures the observed mechanics. Observation from high speed video and simulation reveals that at low f, there is little slip of the limb through the GM, and forward speed is set by step length. At higher f, limbs slip continuously through the GM and fluidize the surrounding material. In this regime, speed is dominated by fluid-like thrust forces.
This thesis explores the design of systems that can climb vertical surfaces with non-negligible d... more This thesis explores the design of systems that can climb vertical surfaces with non-negligible dynamics in the sagittal plane. The development of a low-dimensional model addresses a lack of understanding of sagittal-plane dynamics during climbing in the space of reduced-order dynamic models of legged systems. Using a construction derived from the well-known and well-studied Spring-Loaded Inverted Pendulum (SLIP), we propose a two-legged system with both torsional and linear compliance driven by a position-controlled rotational actuator. Two simple foot models are considered to explore their e↵ect on the dynamics and stability of the system. Results of the model indicate the existence of passively stable gaits during climbing as well as during inverted running and also suggest mechanical tuning parameters for physical climbing systems. A robotic platform capable of producing dynamic climbing behaviors is introduced. A reduced profile, sprawled posture, and improved internal mechanics allow the CLASH platform to be adapted to di↵erent climbing substrates. A passive claw engagement mechanism is proposed and tested with simulated steps to verify the design. With these mechanisms, CLASH becomes the first robotic platform capable of climbing loose cloth and climbs vertically at 15cm/s or 1.5 body-lengths per second. When climbing ferromagnetic surfaces, the system is capable of climbing at 1.8 body-lengths per second. To climb smooth, hard surfaces, a foot with a passively aligning ankle with a tendon-loaded gecko-inspired adhesive is designed and tested using simulated steps. With these engagement mechanisms, the system is able to climb at 1 body-length per second on acrylic with a 70 incline. A simple foot-impact model is created to explain the robot's inability to climb faster or up steeper inclines due to the sagittal-plane reaction forces created during rapid running. i To my two ladies, Alexis and Nina. And to any others that want to join our little clan.
A high-performance, lightweight prototype robotic leg using series-elastic actuation was develope... more A high-performance, lightweight prototype robotic leg using series-elastic actuation was developed in previous work to study the effects of series-elastic actuation in vertical jumping. However, there was also a desire to perform other high-speed dynamic motions with the leg such as cycling. To this end, the thesis goals were focused on improving the existing embedded controller as well as implementing a high-speed cycling function. An analog potentiometer was used to replace a faulty sensor at the knee joint, which houses the compliant element of the series-elastic actuator. Changes were made to the previous controller hardware and software in order to utilize the data available from this new sensor. Using several new functions, a smooth cyclical trajectory was created and followed by the robotic leg at high speeds. The entire cycle was completed in less than 0.5 seconds with a stroke of more than 15cm. These functions will open the path for development of precise trajectory control in future robotic legs, as well as allow for the study of series-elastic actuation through a new dynamic motion. The design of the aforementioned changes and functions are discussed. The significance of the thesis results is discussed, as well as the expected course of future work.
Abstract………………………………………………………………………………….....v Acknowledgments………………………………………………..……………..………...vi ... more Abstract………………………………………………………………………………….....v Acknowledgments………………………………………………..……………..………...vi List of Figures…………………………………….…………………..…..…………..…...vii
A high-performance, lightweight prototype robotic leg using series-elastic actuation was develope... more A high-performance, lightweight prototype robotic leg using series-elastic actuation was developed in previous work to study the effects of series-elastic actuation in vertical jumping. However, there was also a desire to perform other high-speed dynamic motions with the leg such as cycling. To this end, the thesis goals were focused on improving the existing embedded controller as well as implementing a high-speed cycling function. An analog potentiometer was used to replace a faulty sensor at the knee joint, which houses the compliant element of the series-elastic actuator. Changes were made to the previous controller hardware and software in order to utilize the data available from this new sensor. Using several new functions, a smooth cyclical trajectory was created and followed by the robotic leg at high speeds. The entire cycle was completed in less than 0.5 seconds with a stroke of more than 15cm. These functions will open the path for development of precise trajectory control in future robotic legs, as well as allow for the study of series-elastic actuation through a new dynamic motion. The design of the aforementioned changes and functions are discussed. The significance of the thesis results is discussed, as well as the expected course of future work.
This thesis explores the design of systems that can climb vertical surfaces with non-negligible d... more This thesis explores the design of systems that can climb vertical surfaces with non-negligible dynamics in the sagittal plane. The development of a low-dimensional model addresses a lack of understanding of sagittal-plane dynamics during climbing in the space of reduced-order dynamic models of legged systems. Using a construction derived from the well-known and well-studied Spring-Loaded Inverted Pendulum (SLIP), we propose a two-legged system with both torsional and linear compliance driven by a position-controlled rotational actuator. Two simple foot models are considered to explore their e↵ect on the dynamics and stability of the system. Results of the model indicate the existence of passively stable gaits during climbing as well as during inverted running and also suggest mechanical tuning parameters for physical climbing systems. A robotic platform capable of producing dynamic climbing behaviors is introduced. A reduced profile, sprawled posture, and improved internal mechanics allow the CLASH platform to be adapted to di↵erent climbing substrates. A passive claw engagement mechanism is proposed and tested with simulated steps to verify the design. With these mechanisms, CLASH becomes the first robotic platform capable of climbing loose cloth and climbs vertically at 15cm/s or 1.5 body-lengths per second. When climbing ferromagnetic surfaces, the system is capable of climbing at 1.8 body-lengths per second. To climb smooth, hard surfaces, a foot with a passively aligning ankle with a tendon-loaded gecko-inspired adhesive is designed and tested using simulated steps. With these engagement mechanisms, the system is able to climb at 1 body-length per second on acrylic with a 70 incline. A simple foot-impact model is created to explain the robot's inability to climb faster or up steeper inclines due to the sagittal-plane reaction forces created during rapid running. i To my two ladies, Alexis and Nina. And to any others that want to join our little clan.
Exceptional performance is often considered to be elegant and free of 'errors' or misstep... more Exceptional performance is often considered to be elegant and free of 'errors' or missteps. During the most extreme escape behaviours, neural control can approach or exceed its operating limits in response time and bandwidth. Here we show that small, rapid running cockroaches with robust exoskeletons select head-on collisions with obstacles to maintain the fastest escape speeds possible to transition up a vertical wall. Instead of avoidance, animals use their passive body shape and compliance to negotiate challenging environments. Cockroaches running at over 1 m or 50 body lengths per second transition from the floor to a vertical wall within 75 ms by using their head like an automobile bumper, mechanically mediating the manoeuvre. Inspired by the animal's behaviour, we demonstrate a passive, high-speed, mechanically mediated vertical transitions with a small, palm-sized legged robot. By creating a collision model for animal and human materials, we suggest a size depende...
FigS1_v1.ai from Transition by head-on collision: mechanically mediated manoeuvres in cockroaches and small robots
Exceptional performance is often considered to be elegant and free of 'errors' or misstep... more Exceptional performance is often considered to be elegant and free of 'errors' or missteps. During the most extreme escape behaviours, neural control can approach or exceed its operating limits in response time and bandwidth. Here we show that small, rapid running cockroaches with robust exoskeletons select head-on collisions with obstacles to maintain the fastest escape speeds possible to transition up a vertical wall. Instead of avoidance, animals use their passive body shape and compliance to negotiate challenging environments. Cockroaches running at over 1 m or 50 body lengths per second transition from the floor to a vertical wall within 75 ms by using their head like an automobile bumper, mechanically mediating the manoeuvre. Inspired by the animal's behaviour, we demonstrate a passive, high-speed, mechanically mediated vertical transitions with a small, palm-sized legged robot. By creating a collision model for animal and human materials, we suggest a size depende...
S3_video_T_480p.mov from Transition by head-on collision: mechanically mediated manoeuvres in cockroaches and small robots
Exceptional performance is often considered to be elegant and free of 'errors' or misstep... more Exceptional performance is often considered to be elegant and free of 'errors' or missteps. During the most extreme escape behaviours, neural control can approach or exceed its operating limits in response time and bandwidth. Here we show that small, rapid running cockroaches with robust exoskeletons select head-on collisions with obstacles to maintain the fastest escape speeds possible to transition up a vertical wall. Instead of avoidance, animals use their passive body shape and compliance to negotiate challenging environments. Cockroaches running at over 1 m or 50 body lengths per second transition from the floor to a vertical wall within 75 ms by using their head like an automobile bumper, mechanically mediating the manoeuvre. Inspired by the animal's behaviour, we demonstrate a passive, high-speed, mechanically mediated vertical transitions with a small, palm-sized legged robot. By creating a collision model for animal and human materials, we suggest a size depende...
S2_video_T_720p.mov from Transition by head-on collision: mechanically mediated manoeuvres in cockroaches and small robots
Exceptional performance is often considered to be elegant and free of 'errors' or misstep... more Exceptional performance is often considered to be elegant and free of 'errors' or missteps. During the most extreme escape behaviours, neural control can approach or exceed its operating limits in response time and bandwidth. Here we show that small, rapid running cockroaches with robust exoskeletons select head-on collisions with obstacles to maintain the fastest escape speeds possible to transition up a vertical wall. Instead of avoidance, animals use their passive body shape and compliance to negotiate challenging environments. Cockroaches running at over 1 m or 50 body lengths per second transition from the floor to a vertical wall within 75 ms by using their head like an automobile bumper, mechanically mediating the manoeuvre. Inspired by the animal's behaviour, we demonstrate a passive, high-speed, mechanically mediated vertical transitions with a small, palm-sized legged robot. By creating a collision model for animal and human materials, we suggest a size depende...
Exceptional performance is often considered to be elegant and free of 'errors' or misstep... more Exceptional performance is often considered to be elegant and free of 'errors' or missteps. During the most extreme escape behaviours, neural control can approach or exceed its operating limits in response time and bandwidth. Here we show that small, rapid running cockroaches with robust exoskeletons select head-on collisions with obstacles to maintain the fastest escape speeds possible to transition up a vertical wall. Instead of avoidance, animals use their passive body shape and compliance to negotiate challenging environments. Cockroaches running at over 1 m or 50 body lengths per second transition from the floor to a vertical wall within 75 ms by using their head like an automobile bumper, mechanically mediating the manoeuvre. Inspired by the animal's behaviour, we demonstrate a passive, high-speed, mechanically mediated vertical transitions with a small, palm-sized legged robot. By creating a collision model for animal and human materials, we suggest a size depende...
Supplementary material from "Transition by head-on collision: mechanically mediated manoeuvres in cockroaches and small robots
Exceptional performance is often considered to be elegant and free of 'errors' or misstep... more Exceptional performance is often considered to be elegant and free of 'errors' or missteps. During the most extreme escape behaviours, neural control can approach or exceed its operating limits in response time and bandwidth. Here we show that small, rapid running cockroaches with robust exoskeletons select head-on collisions with obstacles to maintain the fastest escape speeds possible to transition up a vertical wall. Instead of avoidance, animals use their passive body shape and compliance to negotiate challenging environments. Cockroaches running at over 1 m or 50 body lengths per second transition from the floor to a vertical wall within 75 ms by using their head like an automobile bumper, mechanically mediating the manoeuvre. Inspired by the animal's behaviour, we demonstrate a passive, high-speed, mechanically mediated vertical transitions with a small, palm-sized legged robot. By creating a collision model for animal and human materials, we suggest a size dependence favouring mechanical mediation below 1 kg that we term the 'Haldane limit'. Relying on the mechanical control offered by soft exoskeletons represents a paradigm shift for understanding the control of small animals and the next generation of running, climbing, and flying robots where the use of the body can off-load the demand for rapid sensing and actuation.
Exceptional performance is often considered to be elegant and free of ‘errors’ or missteps. Durin... more Exceptional performance is often considered to be elegant and free of ‘errors’ or missteps. During the most extreme escape behaviours, neural control can approach or exceed its operating limits in response time and bandwidth. Here we show that small, rapid running cockroaches with robust exoskeletons select head-on collisions with obstacles to maintain the fastest escape speeds possible to transition up a vertical wall. Instead of avoidance, animals use their passive body shape and compliance to negotiate challenging environments. Cockroaches running at over 1 m or 50 body lengths per second transition from the floor to a vertical wall within 75 ms by using their head like an automobile bumper, mechanically mediating the manoeuvre. Inspired by the animal's behaviour, we demonstrate a passive, high-speed, mechanically mediated vertical transitions with a small, palm-sized legged robot. By creating a collision model for animal and human materials, we suggest a size dependence favo...
We study the detailed locomotor mechanics of a small, lightweight robot (DynaRoACH, 10 cm, 25 g) ... more We study the detailed locomotor mechanics of a small, lightweight robot (DynaRoACH, 10 cm, 25 g) which can move on a granular substrate of closely packed 3 mm diameter glass particles at speeds up to 50 cm/s (5 body length/s), approaching the performance of small, highperforming, desert-dwelling lizards. To reveal how the robot achieves this high performance, we used high speed imaging to capture kinematics, and developed a numerical multi-body simulation of the robot coupled to an experimentally validated discrete element method (DEM) simulation of the granular media. Average forward speeds measured in both experiment and simulation agreed well, and increased non-linearly with stride frequency, reflecting a change in the mode of propulsion. At low frequencies, the robot used a quasi-static "rotary walking" mode, in which the granular material yielded as the legs penetrated and then solidified once vertical force balance was achieved. At high frequencies, duty factor decreased below 0.5 and aerial phases occurred. The propulsion mechanism was qualitatively different: the robot ran rapidly by utilizing the speed-dependent fluid-like inertial response of the material. We also used our simulation tool to vary substrate parameters that were inconvenient to vary in experiment (e.g., granular particle friction) to test performance and reveal limits of stability of the robot. Using small robots as physical models, our study reveals a mechanism by which small animals can achieve high performance on granular substrates, which in return advances the design and control of small robots in deformable terrains.
Micro- and Nanotechnology Sensors, Systems, and Applications IV, 2012
Palm sized legged robots show promise for military and civilian applications, including explorati... more Palm sized legged robots show promise for military and civilian applications, including exploration of hazardous or difficult to reach places, search and rescue, espionage, and battlefield reconnaissance. However, they also face many technical obstacles, including-but not limited to-actuator performance, weight constraints, processing power, and power density. This paper presents an overview of several robots from the Biomimetic Millisystems Laboratory at UC Berkeley, including the OctoRoACH, a steerable, running legged robot capable of basic navigation and equipped with a camera and active tail; CLASH, a dynamic climbing robot; and BOLT, a hybrid crawling and flying robot. The paper also discusses, and presents some preliminary solutions to, the technical obstacles listed above plus issues such as robustness to unstructured environments, limited sensing and communication bandwidths, and system integration.
2012 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2012
A 10 cm hexapedal robot is adapted to dynamically climb near-vertical smooth surfaces. A gecko-in... more A 10 cm hexapedal robot is adapted to dynamically climb near-vertical smooth surfaces. A gecko-inspired adhesive is mounted with an elastomer tendon and polymer loop to a remote-center-of-motion ankle that allows rapid engagement with the surface and minimizes peeling moments on the adhesive. The maximum velocity possible while climbing decreases as the incline gets closer to vertical, with the robot able to achieve speeds of 10 cm second −1 at a 70-degree incline. A model is implemented to describe the effect of incline angle on climbing speed and, together with high-speed video evidence, reveals that climbing velocity is limited by robot dynamics and adhesive properties and not by power.
The International Journal of Robotics Research, 2013
We study the locomotor mechanics of a small, lightweight robot (DynaRoACH, 10 cm, 25 g) which can... more We study the locomotor mechanics of a small, lightweight robot (DynaRoACH, 10 cm, 25 g) which can move on a granular substrate of 3 mm diameter glass particles at speeds up to 5 body length/s, approaching the performance of certain desert-dwelling animals. To reveal how the robot achieves this performance, we used high-speed imaging to capture its kinematics, and developed a numerical multi-body simulation of the robot coupled to an experimentally validated simulation of the granular medium. Average speeds measured in experiment and simulation agreed well, and increased nonlinearly with stride frequency, reflecting a change in propulsion mode. At low frequencies, the robot used a quasi-static “rotary walking” mode, in which the substrate yielded as legs penetrated and then solidified once vertical force balance was achieved. At high frequencies the robot propelled itself using the speed-dependent fluid-like inertial response of the material. The simulation allows variation of parame...
S1_video_T_720p.mov from Transition by head-on collision: mechanically mediated manoeuvres in cockroaches and small robots
Exceptional performance is often considered to be elegant and free of 'errors' or misstep... more Exceptional performance is often considered to be elegant and free of 'errors' or missteps. During the most extreme escape behaviours, neural control can approach or exceed its operating limits in response time and bandwidth. Here we show that small, rapid running cockroaches with robust exoskeletons select head-on collisions with obstacles to maintain the fastest escape speeds possible to transition up a vertical wall. Instead of avoidance, animals use their passive body shape and compliance to negotiate challenging environments. Cockroaches running at over 1 m or 50 body lengths per second transition from the floor to a vertical wall within 75 ms by using their head like an automobile bumper, mechanically mediating the manoeuvre. Inspired by the animal's behaviour, we demonstrate a passive, high-speed, mechanically mediated vertical transitions with a small, palm-sized legged robot. By creating a collision model for animal and human materials, we suggest a size depende...
ABSTRACT We present an experimental and computer simulation study of a small, light-weight, biolo... more ABSTRACT We present an experimental and computer simulation study of a small, light-weight, biologically inspired robot running on a model granular medium (GM), 3 mm diameter glass particles. The six-legged RoACH robot (10 cm long, 25 grams) utilizes an alternating tripod gait to run at speeds up to 25 cm/sec. Forward speed increases with increasing limb frequency 0<f<12 Hz. An experimentally validated discrete element method (DEM) simulation of the device captures the observed mechanics. Observation from high speed video and simulation reveals that at low f, there is little slip of the limb through the GM, and forward speed is set by step length. At higher f, limbs slip continuously through the GM and fluidize the surrounding material. In this regime, speed is dominated by fluid-like thrust forces.
Uploads
Papers by Paul Birkmeyer