Hybrid Robotic Control With Compliance-Aware Trajectory Adjustment

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Solution Overview

Problem

Traditional robotic systems face limitations in dynamic environments due to assumptions of rigid connections and unchanged conditions, leading to inaccurate position and force control, which can result in task failure or damage.

Innovation Solution

A robotic control system that includes force and position sensors, a controller with executable instructions to receive and process actual and desired forces and positions, and modify trajectories based on hybrid weighting values to account for compliance and environmental changes, enabling adaptive control between force and position control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If traditional rigid connection assumptions are used in robotic control, then control simplicity is maintained, but position and force accuracy deteriorate due to compliance in real connections

Engineering Contradiction:

Improvecontrol process simplicityVSAvoidposition and force accuracy

Core Design Contradiction:

Device complexityVSMeasurement precision

Solution Approach 1:

The patent transforms the control approach by changing the fundamental parameter assumption from rigid connections to compliant connections. It introduces compliance parameters ( stiffness and damping coefficients) to model real-world connections, allowing the control system to account for mechanical flexibility and achieve accurate position and force control despite compliance in the robotic system

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If additional position sensors are added to improve position accuracy, then measurement precision improves, but device complexity increases

Engineering Contradiction:

Improveposition accuracyVSAvoidsensor quantity

Core Design Contradiction:

Measurement precisionVSDevice complexity

Solution Approach 1:

The patent replaces additional mechanical position sensors with a computational approach. By using the existing force sensor data and implementing a hybrid force/position control algorithm with compliance modeling, the system achieves accurate position estimation without requiring extra position sensing hardware, thus avoiding increased device complexity

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Adaptability or versatility

If force control is used to handle compliant connections, then adaptability to real-world conditions improves, but position control precision deteriorates

Engineering Contradiction:

Improvecompliance handling capabilityVSAvoidposition control accuracy

Core Design Contradiction:

Adaptability or versatilityVSMeasurement precision

Solution Approach 1:

The patent merges force control and position control into a hybrid control framework. The control law combines force control outputs (which handle compliance well) with position control outputs (which provide position accuracy) through a weighting mechanism. This allows the system to simultaneously achieve adaptability to compliant connections and precision in position control by leveraging the strengths of both control modes

Inventive Principle:

Principle #5Merging (Combining)

Data Source

PatentUS11691280B2Hybrid control of a robotic system

Publication Date: 2023.07.04 THE CLEVELAND CLINIC FOUND

AI summary

An object can be moved via a robotic system with a combination of force and position control. The control system can include the object to be moved, the robotic system that moves the object, at least one force sensor, at least one position sensor, and a controller. A position control output, a force control output, and a hybrid weighting value can each be determined by the controller based on sensor data and then combined to determine an amount of position control and/or force control to be applied to move the object and/or modify an object in motion's trajectory.