Hexapods

List of interesting/relevant biologically inspired hexapods

RiSE

Institution: University of Pennsylvania Animal Inspiration: Geckos, cockroaches, squirrels

Publications
Spenko, M.J., Haynes, G.C., Saunders, J.A., Cutkosky, M.R., Rizzi, A.A., Full, R.J. and Koditschek, D.E. (2008), Biologically inspired climbing with a hexapedal robot. J. Field Robotics, 25: 223-242.

Fast Facts
Actuation:	Geared DC motors (Maxon RE16 4.5-W)
DoF per Leg	2 (Full range of motion generated by passive compliance and 4-bar mechanism)
Controller	Feedforward gait generation (open-loop)
Sensing	Strain gauges on limbs (force sensing)

• Tail segment to, "reduce pull in forces required at the front limbs"

• Modular design to allow for 4 leg (gecko) and 6 leg (cockroach) configurations

• Compliant toes and ankles to grip walls

• Leg compliance through shock absorbers to ensure grip when climbing, walking

HECTOR

Institution: Bielefeld University Animal Inspiration: Stick insect (Carausius morosus)

Publications
https://doi.org/10.3389/fnbot.2019.00088
Schneider A., Paskarbeit J., Schilling M., Schmitz J. (2014) HECTOR, A Bio-Inspired and Compliant Hexapod Robot. In: Biomimetic and Biohybrid Systems. Living Machines 2014. Lecture Notes in Computer Science, vol 8608. Springer, Cham.

Fast Facts
Actuation	DC motors with harmonic gearboxes (custom drive)
DoF per Leg	3
Controller	WalkNet (non-morphological SNS)
Sensing	Joint torque and position (actuators) Ground contact (foot touch sensors) Limb strain (strain gauges in biologically plausible positions)

• Series elasticity in joints via elastomer couplings in gearboxes

MantisBot

Institution: Case Western Reserve University Animal Inspiration: Praying mantis (Tenodera sinensis)

Publications
Nicholas S. Szczecinski, Andrew P. Getsy, Joshua P. Martin, Roy E. Ritzmann, Roger D. Quinn. Mantisbot is a robotic model of visually guided motion in the praying mantis. 2017. Arthropod Structure & Development. Volume 46, Issue 5. pp. 736-751
Szczecinski N.S., Quinn R.D. (2017) MantisBot Changes Stepping Speed by Entraining CPGs to Positive Velocity Feedback. In: Biomimetic and Biohybrid Systems. Living Machines 2017. Lecture Notes in Computer Science, vol 10384. Springer, Cham.
Nicholas S Szczecinski and Roger D Quinn. Template for the neural control of directed stepping generalized to all legs of MantisBot. 2017. Bioinspir. Biomim. 12 045001
N. S. Szczecinski et al., "Introducing MantisBot: Hexapod robot controlled by a high-fidelity, real-time neural simulation," 2015 IEEE/RSJ International Conference on Intelligent Robots and Systems (IROS), 2015, pp. 3875-3881

Fast Facts
Actuation	DC Servomotors (Dynamixel MX-64, AX-12)
DoF per Leg	4 in middle, hind 5 in front
Controller	synthetic nervous system
Sensing	Joint torque, position and velocity (actuators) Limb strain (strain gauges in biologically plausible locations)

• Has prothorax segment that can pitch and yaw with respect to thorax via linkage assembly

LAURON V

Institution: FZI Research Center for Information Technology Animal Inspiration: Stick insect (loosely)

Publications
A. Roennau, G. Heppner, M. Nowicki and R. Dillmann, "LAURON V: A versatile six-legged walking robot with advanced maneuverability," 2014 IEEE/ASME International Conference on Advanced Intelligent Mechatronics, 2014, pp. 82-87

Fast Facts
Actuation	Geared DC motors
DoF per Leg	4
Controller	Behavior based control system
Sensing	IR camera Stereo camera

• Used "Yoshikawa workspace analysis" to determine leg configuration and mounting angles

• Abdomen holds control PC

• Head with 2 DoF

• Has a spring damper in each foot

• Has optional gripper arm for manipulation

AMOS II

Institution: Georg-August-Universität Göttingen Animal Inspiration: Stick insects, cockroaches, ants

Publications
Dennis Goldschmidt, Florentin Wörgötter, Poramate Manoonpong. 2014. Biologically-inspired adaptive obstacle negotiation behavior of hexapod robots. Vol. 8

Fast Facts
Actuation	Geared DC servomotors
DoF per Leg	3
Controller	Biomimetic neural simulation with neural learning
Sensing	2 ultrasonic sensors on front body part 6 foot contact sensors 6 reflex infrared sensors on front of legs Current sensor Inclinometer sensor 3 light dependent resistors on front body part USB camera on front body part Laser scanner on front body part

• Has actuated hinge joint (backbone joint; BJ) connecting the two parts of its body

  • Enables controlled flexibility in the thorax

  • One pair of legs on front section, two pairs on rear

• Used LpzRobots to simulate robot first to double check neural network controller

Messor II

Institution: Poznan University of Technology Animal Inspiration: Insects

Publications
Belter D., Walas K. (2014) A Compact Walking Robot – Flexible Research and Development Platform. In: Szewczyk R., Zieliński C., Kaliczyńska M. (eds) Recent Advances in Automation, Robotics and Measuring Techniques. Advances in Intelligent Systems and Computing, vol 267. pp 343-352 Springer, Cham.

Fast Facts
Actuation	Servomotors (Dynamical RX-28)
DoF per Leg	3
Controller	Tradition autonomous control (Sense-Plan-Act)
Sensing	Vision (RGB-D cameras) Exteroceptive sensor (Kinect, Joint position, velocity, torque Leg current/load (ACS712 hall sensor) Body incline (Xsens MTi) Ground contact (micro-switches in feet)

• Relation of the leg segment dimensions is 1.4:3.45:5 (1:4:5 in insects)

BILL-Stick

Institution: University of Edinburgh Animal Inspiration: Praying mantis (Tenodera sinensis)

Publications
W. A. Lewinger, H. M. Reekie and B. Webb, "A hexapod robot modeled on the stick insect, Carausius morosus," 2011 15th International Conference on Advanced Robotics (ICAR), 2011, pp. 541-548

Fast Facts
Actuators	DC Servomotors (Hitec HSR-5990TG)
DoF per Leg	3
Controller	Not strictly biomimetic SNS (CPGs modified by sensory feedback)
Sensing	Joint position Motor current

• 18.8:1 scale representation of the insect

• Parallel elasticity in the CTr joints to help support body weight

• Has abdomen to maintain accurate proportions and shift CoM to biological location

• Each leg has its own, custom-designed controller responsible for controlling the joint actuators

  • Command the joints of a single leg to perform stepping motions, while adapting those motions based on position and load information sensed from the joints

BILL-Ant-A

Institution: Case Western Reserve University Animal Inspiration: Ant

Publications
W. A. Lewinger and R. D. Quinn, "A hexapod walks over irregular terrain using a controller adapted from an insect's nervous system," 2010 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2010, pp. 3386-3391, doi: 10.1109/IROS.2010.5650200.

Fast Facts
Actuators	Servomotors (MPI-MX450)
DoF per Leg	5 (3 active, 2 passive)
Controller	Biomimetic SNS
Sensing	Ground contact (force-sensitive resistor) Light detection Obstacle contact near foot

• 1-DoF articulated neck carries two optical sensors

• Microcontroller in each leg implements the role of the thoracic ganglia and are responsible for:

  • Motor control of the three joints in the leg

  • Reading sensory information from the two passive DoF

  • Sharing leg influence data during its stepping cycle with its adjacent neighboring legs, in order to create coordinated walking gaits

• Uses BrainStem microcontroller to manage goal of moving toward light

Robot II

Institution: Case Western Reserve University Animal Inspiration: Stick insect

Publications
Kenneth S.Espenschied, Roger D.Quinn, Randall D.Beer, Hillel J.Chiel. 1996. Biologically based distributed control and local reflexes improve rough terrain locomotion in a hexapod robot. Volume 18, Issues 1–2. pp. 59-64

Fast Facts
Actuators	DC motors
DoF per Leg	4 (3 active, 1 passive)
Controller	Finite state machine based on Cruse rules
Sensing	Limb force Joint position

• Includes passive compliance via springs in each leg

  • Active compliance by modified properties of actuator control

Robot V (Ajax)

Institution: Case Western Reserve University Animal Inspiration: Death head cockroach (Blaberus discoidalis)

Publications
D. A. Kingsley, R. D. Quinn and R. E. Ritzmann, "A Cockroach Inspired Robot With Artificial Muscles," 2006 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2006, pp. 1837-1842
D.A. Kingsley. 2005. A COCKROACH INSPIRED ROBOT WITH ARTIFICIAL MUSCLES. PhD Thesis.

Fast Facts
Actuators	Braided pneumatic actuators
DoF per Leg	5 in front leg 4 in middle leg 3 in hind leg
Controller	Biomimetic, neural inspired controller
Sensing	Joint position, torque

• Passively compliant feet via springs in tubes

• Parallel elasticity in CTr and Beta joints

• Has abdomen for accurate CoM

DLR-Crawler

Institution: DLR-German AeroSpace Center Animal Inspiration: Human hand

Publications
M. Gorner et al., "The DLR-Crawler: A testbed for actively compliant hexapod walking based on the fingers of DLR-Hand II," 2008 IEEE/RSJ International Conference on Intelligent Robots and Systems, 2008, pp. 1525-1531

Fast Facts
Actuators	Geared DC motors
DoF per Leg	3
Controller	Force and position control algorithms
Sensing	Joint position and torque Motor position, temperature Vision Body speed and orientation Foot force

• Add compliance via software