Hybrid Serial-Parallel Robot Control for Compliant Payload Handling

Resolve Bottlenecks,
Find Innovative SolutionsGenerate Solutions

Solution Overview

Problem

Rigid payloads are susceptible to strain-related damage due to position errors during manipulation and operation in multi-robot cooperative payload control systems, as existing technologies lack effective means to protect such payloads from undue strain.

Innovation Solution

A scalable control architecture using a distributed control system that coordinates the motion of multiple robots, including serial and parallel robots, with real-time monitoring and regulation of robot-specific motions and force actions to ensure compliant and gentle handling of the payload, employing a coordinated motion controller for serial robots and a corrective motion controller for the parallel robot to mitigate strain.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of moving object

If serial robots are used to manipulate rigid payloads, then the robots can achieve large range of motion, but position errors cause strain and damage to the payload

Engineering Contradiction:

Improverange of motionVSAvoidstrain on payload

Core Design Contradiction:

Length of moving objectVSObject-affected harmful factors

Solution Approach 1:

The patent combines serial robots (providing large range of motion) with parallel robots (providing high stiffness and position accuracy) in a hybrid configuration. The serial-parallel robot system merges the advantages of both configurations, allowing the serial portion to achieve large workspace while the parallel portion maintains high positioning accuracy and reduces strain on rigid payloads.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The patent employs a composite control strategy that integrates coordinated motion control for serial robots and corrective motion control for parallel robots. This composite control approach combines different control methodologies to simultaneously achieve large range of motion and high position accuracy, thereby preventing strain on rigid payloads.

Inventive Principle:

Principle #40Composite materials

2Measurement precision

If parallel robots are used for payload manipulation, then position accuracy is improved, but the range of motion is reduced

Engineering Contradiction:

Improveposition accuracyVSAvoidrange of motion

Core Design Contradiction:

Measurement precisionVSLength of moving object

Solution Approach 1:

The patent segments the robotic system into serial and parallel portions, where the serial segment provides large range of motion and the parallel segment provides high position accuracy. This segmentation allows each subsystem to optimize for its specific function while working together to achieve both large workspace and high precision.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The patent extends the system from purely parallel or purely serial configuration to a hybrid serial-parallel configuration, adding a new dimensional aspect to the kinematic chain. This dimensional change allows the system to simultaneously access large workspace (from serial portion) and high precision (from parallel portion).

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Adaptability or versatility

If multiple robots operate simultaneously on rigid payloads, then collaborative tasks are enabled, but coordination errors cause undue strain

Engineering Contradiction:

Improvecollaborative capabilityVSAvoidstrain from position errors

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

The patent implements a feedback-based corrective motion control system where the parallel robot's controller continuously monitors position errors and adjusts its motion in real-time to compensate for coordination discrepancies. This feedback mechanism ensures that collaborative tasks can be performed by multiple robots while maintaining high position accuracy and preventing strain on rigid payloads.

Inventive Principle:

Principle #23Feedback

4Weight of moving object

If serial robots with high inertia are used, then payload capacity is increased, but response time decreases

Engineering Contradiction:

Improvepayload capacityVSAvoidresponse time

Core Design Contradiction:

Weight of moving objectVSSpeed

Solution Approach 1:

The patent employs dynamic control strategies that adapt the control parameters based on the current operational state. The coordinated motion controller and corrective motion controller work together to optimize the response characteristics, allowing the high-inertia serial robots to maintain payload capacity while achieving faster response times through dynamic adjustment of control gains and trajectories.

Inventive Principle:

Principle #15Dynamics

Data Source

PatentUS11638995B2Compliant payload presentation using robotic system with coordinated serial and parallel robots

Publication Date: 2023.05.02 GM GLOBAL TECHNOLOGY OPERATIONS LLC

AI summary

A robotic system for presenting a payload within a workspace includes a pair of serial robots configured to connect to the payload, a parallel robot coupled to a distal end of one of the serial robots such that the parallel robot is disposed between the distal end and the payload, a sensor situated within a kinematic chain extending between the distal end and the payload, and a robot control system (RCS). The sensor outputs a sensor signal indicative of a measured property of the payload. The RCS includes a coordinated motion controller configured to control the serial robots, and a corrective motion controller configured to control the parallel robot. Parallel robot control occurs in response to the sensor signal concurrently with control of the serial robots in order to thereby modify the property of the payload in real-time.