Inertially Significant Humanoid Teleoperation via Whole Body Model Predictive Control and Online Parameter Estimation
Organizations: Robotics Lab, Florida Institute for Human & Machine Cognition, USA · Intelligent Systems & Robotics, University of West Florida, USA
Abstract
The effective deployment of humanoid robots in practical tasks of interest will require a capability of sensing and adapting to variations in inertial parameters, as occurs during heavy tool use or when carrying significant payload. Such payloads constitute a significant proportion of the combined payload-robot system, the effects of which cannot be ignored by delegating to feedback control. This paper showcases a general solution to this problem by integrating a whole body model predictive controller (WB-MPC) with an extended Kalman filter (EKF) for online estimation of fully physically consistent time-varying inertial parameters. These estimates are fed through to the WB-MPC's full rigid body dynamics model, resulting in more accurate feedforward torques for task demands under external load. Additionally, a virtual reality (VR) interface is provided that enables an operator to provide task-specific references without regard to payload while delegating dynamic balance to the WB-MPC. The framework is validated with simulation and hardware experiments on a humanoid system.
Figures & tables
| Cost | Residual | Type | Activation | Standard reference |
|---|---|---|---|---|
| Upper body jointspace tracking | order | Weighted Quad. | Home config., zero velocity | |
| Center of mass tracking | order | Weighted Quad. | ||
| Pelvis orientation | order | Weighted Quad. | (quaternion) | |
| Foot placement | order | Weighted Quad. | Home config. equivalent | |
| Angular momentum | order | Weighted Quad. | ||
| Lower body state regularization | Standard | Weighted Quad. | Home config., zero velocity |
| WB-MPC cost term | VR operator input |
|---|---|
| Arm jointspace | Handheld controllers |
| Spine jointspace | Right thumbstick, horizontal |
| Pelvis pitch | Right thumbstick, vertical |
| Center of mass height | Left thumbstick, vertical |
| Parameter | Value |
|---|---|
| Process : | |
| Process : , , | |
| Prior : , | |
| Prior : , | — |
| Measurement : floating base, spine | |
| Measurement : arms, legs |
| Condition | RMSE [mm] | RMSE [mm] |
|---|---|---|
| No estimator | 67.8 | 389.2 |
| With estimator | 6.4 | 14.2 |
| Elbow RMSE | RMS deviation from nominal | ||||
|---|---|---|---|---|---|
| Prior regime | [deg] | ||||
| No prior | 1.27 | 1.11 | 0.11 | 0.09 | 0.28 |
| Inertia-only | 1.27 | 1.11 | 0.28 | ||
| Dimension | Mean [m] | Min [m] | Max [m] | Spread [m] |
|---|---|---|---|---|
| RMSE [mm] | Bias [mm] | |||
|---|---|---|---|---|
| Condition | ||||
| Unloaded | 14.2 | 13.2 | ||
| Loaded (4.5 kg) | 19.3 | 22.4 | ||
Humanoid Robot Control
Humanoid robot control develops methods for coordinating bipedal balance, locomotion, and whole-body interaction with people and objects.
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