Omnidirectional wheeled humanoid robot based on a linear predictive position and velocity controller

Patent metadata

Field	Value
Publication number	US-10293486-B2
Application number	US-201515300218-A
Country	US
Kind code	B2
Filing date	Apr 17, 2015
Priority date	Apr 17, 2014
Publication date	May 21, 2019
Grant date	May 21, 2019

Abstract

A humanoid robot with a body joined to an omnidirectional mobile ground base, and equipped with: a body position sensor and a base position sensor to provide measures, actuators comprising at least 3 wheels located in the omnidirectional mobile base, extractors for converting the measures into useful data, a controller to calculate position, velocity and acceleration commands from the useful data using a robot model and pre-ordered position and velocity references, means for converting the commands into instructions for the actuators, wherein the robot model is a double point-mass model, and wherein the commands are based on a linear model predictive control law with a discretized time according to a sampling time period and a number of predicted samples, and expressed as a quadratic optimization formulation with: a weighted sum of objectives and a set of predefined linear constraints.

First claim

The invention claimed is:

1. A humanoid robot with a body joined to an omnidirectionnal mobile ground base, and equipped with:
a body position sensor and a base position sensor to provide measures,
actuators comprising joints motors and at least 3 wheels located in the omnidirectionnal mobile base, with at least 1 omnidirectional wheel,
extractors for converting the measures into observed data,
a controller to calculate position, velocity and acceleration commands from the observed data using a robot model and pre-ordered position and velocity references,
means for converting the commands into instructions for the actuators,
wherein the robot model is a double point-mass model, and wherein the commands are based on a linear model predictive control law with a discretized time according to a sampling time period and a number of predicted samples, and expressed as a quadratic optimization formulation with:
a weighted sum of:
a base position objective,
a base velocity objective,
an objective related to the distance between the CoP and the base center, CoP being the barycenter of contact forces between the robot and the ground,

with predefined weights and a set of predefined linear constraints which are:
a maximum velocity and acceleration of the mobile base,
a CoP limit.

2. The humanoid robot of claim 1 , wherein a weighted numerical stability objective is added to the weighted sum of objectives.

3. The humanoid robot of claim 1 , wherein the set of predefined linear constraints comprise kinematic limits of the body.

4. A method for controlling a humanoid robot with a body joined to an omnidirectionnal mobile ground base and actuators comprising at least 3 wheels located in the omnidirectionnal mobile base, with at least 1 omnidirectional wheel, comprising the following steps implemented according to a closed-loop scheme:
retrieving position measure of the body and position measure of the base,
converting these position measures in observed position measures,
calculating body velocity and base velocity commands using a control law based on a linear model predictive control law with a discretized time according to a sampling time period and a number of predicted samples, and expressed as a quadratic optimization formulation with a weighted sum of
a base position objective,
a base velocity objective,
an objective related to the distance between the CoP and the mobile base center, CoP being the barycenter of contact forces between the robot and the ground,

with predefined weights and a set of linear constraints which are
a maximum velocity and acceleration of the mobile base,
a CoP limit,

converting these commands into instructions for the robot actuators.

5. The method of claim 4 , wherein the set of predefined linear constraints comprise kinematic limits of the body.

6. The method of claim 4 , wherein a weighted numerical stability objective is added to the weighted sum of objectives.

7. A non-transitory computer readable storage medium containing a computer program comprising computer code instructions configured to execute on a computer the method of claim 4 .

Assignees

• Softbank Robotics Europe
• Institut National De Rech En Informatique Et En Automatique

Inventors

• Lafaye Jory
• Gouaillier David
• Wieber Pierre-Brice

Classifications

• B25J9/1669 Primary

  characterised by special application, e.g. multi-arm co-operation, assembly, grasping · CPC title

• G05D1/0891

  specially adapted for land vehicles · CPC title

• B25J9/1628 Primary

  characterised by the control loop · CPC title

• B25J5/007 Primary

  mounted on wheels · CPC title

• G05D2201/0217

  Physics · mapped topic