design specifications and compliant actuation concepts of ... · • f2: intrinsic joint elasticity...

Design Specifications and Compliant Actuation Concepts of WALK-MAN

Humanoid

Nikos Tsagarakis

& Human Centered Mechatronics Group @ IIT-ADVR & UNIPI (Manolo Garabini, Manuel Catalano, Antonio Bicchi)

Workshop on the Mechatronic Design of Humanoid Robots: Current and Future Trends

Humanoids 2014, 18-20th November, Madrid, Spain

Special credits

Manuel Catalano

Houman Dallali Enrcico Mingo Alessio Rocchi

Francesca Negrello Manolo Garabini

Wesley Roozing Zhibin Li

2 The Mechatronic Design of Humanoid Robots: Current and Future Trends, Humanoids 2014, 18-20th November, Madrid, Spain

Jerryll Noorden Gia Vo Loc Wooseok Choi

http://www.google.it/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&docid=UJKxKHGooHgxaM&tbnid=LL4MKnwmdQoouM:&ved=0CAUQjRw&url=http://www.centropiaggio.unipi.it/~catalano&ei=Ak-nU5eQHcaN0AWZ1oGIDg&psig=AFQjCNHUaapCMhjxh4drYuTgua9VbCUs8w&ust=1403560060836927

http://www.google.it/url?sa=i&rct=j&q=&esrc=s&source=images&cd=&cad=rja&uact=8&docid=jtgvqAOc635IkM&tbnid=ZqVnoqk7wydqGM:&ved=0CAUQjRw&url=http://it.linkedin.com/pub/manolo-garabini/26/801/52a/en&ei=5N6uU_PtPMbqPJzLgNgM&psig=AFQjCNFt2ncYLR4t6nuVqJFWeGA_S0mcXw&ust=1404055645332952

WALK-MAN EC Project

• Integrated Project (IP), 5 partners

• Coordinator: IIT

• Duration: 48M

• Started: Sept 2013

Whole Body Adaptive Locomotion and MANipulation

www.walk-man.eu IIT-ADVR + iCub Facility


http://www.kit.edu/


Enable robots to demonstrate similar skills and operate in

unstructured spaces designed for humans

Humanoids with Human Level Performance

Robotic actuation Main trends

Electrical Hydraulic

Intrinsically stiff actuation

+

Active impedance regulation

• robustness

• low power density

• efficiency

• efficiency

• safety

Intrinsic compliant actuation

+

Control to satisfy performance indexes

1. lower impact forces, improves robustness 2. passive adaptability to interaction 3. peak power generation 4. energy efficiency


COMAN overview

• 31 DOFs + 2DOF for hands • Actuation

– moderate to high power – passive series compliance

• legs (ankle/knee and hip sagittal joints) • torso (pitch and yaw) • arms: (shoulder and elbow

• Sensing – joint torque sensing – 2 x 6 DOF F/T sensors – IMU

• Power autonomy – battery – power management system

• On board computation power – 2 x PC104 (1 inside the torso and one in the

head)

• Weights 31Kg


COMAN Actuation

Link absolute Encoder

Motor relative encoder

Spring deflection absolute encoder

Torque sensor

Series elastic module

BLDC motor

HD drive

Diameter 70mm

Length 80mm

Peak Torque 55Nm

Max rotary passive

deflection

+/-0.2rad

Weight 0.7Kg

Three key design features

• F1: moderate to high power capacity actuation

• F2: intrinsic joint elasticity for physical robustness

• F3: joint torque sensing and active compliance regulation


Arm/hand modules

• 7DOF Arm

– Torque controlled

– 6 DOF F/T sensor

– passive compliance • shoulder (flex/ext and abd/add) motions

• elbow flex/ext

• Hand

– Developed originally in Pisa (Catalano & Bicchi et al, Humanoids 2012)

– adapted now for IIT-COMAN

– fully articulated, 5 fingers hand

– under-actuated, driven by a single motor with the transmission implementing the first grasping synergy

Catalano et. al., Humanoids 2012

SEA

Joints

Pisa-IIT

Soft Hand


9

Zhibin Li et al, Humanoids 2012

Perrin et al, IROS 2013

10 Journées Nationales du GdR Robotique 2014, 29-30th Octomber Paris, France

Zhibin Li, Xin Wang, et al

Ajoudani , Lee et all Humanoids 2014 Rocchi, Mingo et all ICRA 2015 (submitted)

WALK-MAN Humanoid

High power and energy efficient

drives

Compliant under-actuated hands

Powerful and robust compliant

arms

Light weight agile legs Joint Torque

sensing

Compliant feet

Long/short range stereo vision

Robust shock absorbing and

impact protection covers

Force sensing

11 Workshop on Cognitive Humanoid Robotics Research, 18th November 2014, Madrid, Spain

Generic subtasks/interaction scenarios of the robot deployment


WALK-MAN robot specifications

• Robot Size and Kinematics.

• Joint Range of motion

• Joint strength requirements

• Design features for Robust Physical Interaction – Actuation specifications and design approach

– End effectors

• Perception system

• Power Autonomy

• Computation and Control Requirements

• Command and Control Interface


Primitive High Strength/Power (HSP) Tasks HSP Task 10: Front Fast Stepping (0.3sec) to recover balance

0

50

100

150

200

250

300

350

Motor Torque

Nm

L.A.P.L.K.L.H.P.R.A.P.R.K.R.H.P.

0

200

400

600

800

1000

1200

Motor Power

Watt

s

L.A.P.L.K.L.H.P.R.A.P.R.K.R.H.P.

0 0.05 0.1 0.15 0.2 0.25 0.3-1

-0.5

0

0.5

1

1.5

time (sec)

rad

R.H.P.

R.K.

R.A.P.

L.H.P.

L.K.

L.A.P.

0 0.05 0.1 0.15 0.2 0.25 0.3-1000

-500

0

500

1000

1500

time (sec)

Watt

s

R.H.P.

R.K.

R.A.P.

L.H.P.

L.K.

L.A.P.

0 0.05 0.1 0.15 0.2 0.25 0.3-12

-10

-8

-6

-4

-2

0

2

4

6

time (sec)

Speed r

ad/s

ec

R.H.P.

R.K.

R.A.P.

L.H.P.

L.K.

L.A.P.

0 0.05 0.1 0.15 0.2 0.25 0.3-300

-200

-100

0

100

200

300

400

time (sec)

To

rqu

e N

.m

R.H.P.

R.K.

R.A.P.

L.H.P.

L.K.

L.A.P.


Power branch (PB)

• Custom high performance frameless BLDC motor – improved strength and resistivity at

high temperatures

– 800W continuous power at 100°C rise, nominal peak power: 2.9KW

• Gearing : 80/1

• Joint torque/speed – Static Peak torque 270Nm

– Dynamic Peak torque 220Nm

– speed at dynamic peak torque 11-12rad/sec (at 48V)

• Full feedback – High resolution absolute encoders

(19bit)

– Torque encoder sensing • Resolution: 25mNm

• Max offset: 0.5Nm

– Weight: 2.0Kg


• Elastic Element:

– Torsion Bar • Material: Titanium

• Dimension: – 200 Nm > De 19 mm, Di 16 mm, L 97 mm

– 140 Nm > De 15.6 , Di 12.6 mm, L 77 mm

– Safety Factor: 2

Output Shaft

Harmonic Drive

Torsion Bar

WALK-MAN Actuation Principles Power Branch (PB)


WALK-MAN Actuation Principles Custom driver Electronics

100mm • Hard real time Communication interface (EtherCAT) • A single DSP for each motor

– TMS320F28335 (32bit, 150MHz)

• Control – 20KHz Current loop – 5KHz Torque loop – 2KHz Impedance loop

– Accurate current measurement for each motor phase.

• Several Analogue & Digital I/O ports • Power inverter

– Power bus: up to 140V – Local power up/down control through

EtherCAT – High current (120A continuous, 300A peak) – Regenerative energy capability

• Fully integrated in the motor assembly

35mm



Specification

A

B

C

Continues Power (W) @ 120C rise 900 500 222

Intermediate Mechanical Power operating

point (G=80:1, eff=70%)

[email protected]/s

1300W

[email protected]/s

1040W

[email protected]/s

305W

Dynamic Peak Mechanical Power operating point, (G=80:1, eff=70%)

220Nm (10.4rad/sec) 2280W

140Nm (11.2rad/sec) 1560W

40 Nm(9.3rad/s) 370W

Static Peak Torque (Nm), (G=80:1, eff=90%)

270Nm 180Nm 52Nm

No load speed (rpm) 14rad/s 16.7rad/s 11.3rad/s

Weight (kg) 2.0 1.5 0.7

Stiffness (Nm/rad) 2600 2000 1500

Overall dimensions DxL (mm) 110x150 100x140 (60x100)

One common design Three sizes with three different torque, power and stiffness ranges

In collaboration with University of Pisa


COMAN squatting energy example


Asymmetric compliant antagonistic joint

elastic element

Main high power

actuator

Auxiliary lower power

drive

Bi-directional series elastic

coupling

High power branch

Non-backdrivable

coupling

Energy storage branch


Energy storage branch (ESB)

• Energy storage capacity in the ESB is maximized – use an elastic band similar to

shock cords instead of mechanical metal springs.

• Ability to regulate the pre-tension of the elastic element – brushless DC servomotor (100W)

– coupled to a low gear ratio planetary gearhead in series with a highly back-drivable ball screw transmission

– Efficient maintenance of pretension with the use of a two-way overrunning clutch module.

• The force of the elastic band is monitored with a load cell


Energy storage branch (ESB)

• large energy storage capacity

• controllable energy storage and release

• Expected benefit

– efficient operation in cyclic motions

– zero energy static load compensation


Knee joint prototype

High power branch

Energy storage branch


0.5Hz squatting with q=0.8..1.8rad Without and with ESB


0.5Hz squatting with q=0.8..1.8rad Without and with ESB: Power/Torque comparison


Squatting motion

Squatting motion data Improved efficiency

Power and energy storage branch actuation trajectories

Effect on power and torque requirements


Many thanks for your attention


design specifications and compliant actuation concepts of ... · • f2: intrinsic joint elasticity...

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