Overdetermined Motion Platform for Infinite Yaw and 6-DOF Stability
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Solution Overview
Problem
Existing movement platforms with six motors are complex, have low stability, and limited workspace, making them unsuitable for applications like automotive driving simulation, and require complex control systems with potential compliance issues.
Innovation Solution
An overdetermined movement platform system with eight motors connected by push-pull rods, allowing infinite rotational movement and decoupling degrees of freedom, using a model predictive control algorithm to manage force imbalances and maintain stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If six motors are used in a movement platform system, then the system structure is simpler, but the stability is low and workspace is limited
Solution Approach 1:
The patent applies redundancy design by using eight motors instead of six, creating an overdetermined system where the number of actuators exceeds the degrees of freedom. This beforehand cushioning against motor failure ensures that if one or two motors fail, the platform maintains stability and can still be controlled, directly resolving the contradiction between simplicity and stability.
2Device complexity
If six motors are used in a movement platform system, then the system structure is simpler, but the workspace is smaller
Solution Approach 1:
The redundant motor configuration allows the system to access a larger workspace envelope while maintaining control authority throughout the extended range of motion. The extra motors provide the necessary actuation forces at the boundaries of the workspace that would be unavailable in a minimal six-motor configuration.
3Reliability
If eight motors are used in an overdetermined system, then the stability and workspace are improved, but the control complexity increases due to force imbalances
Solution Approach 1:
The control system continuously monitors the positions and forces of all eight motors and dynamically adjusts actuation commands to maintain force balance. This feedback mechanism resolves the force imbalances that arise in overdetermined systems, preventing unwanted platform deformations while preserving the stability and workspace benefits of the redundant configuration.
Solution Approach 2:
The control system performs multiple functions simultaneously: it controls platform position and orientation, distributes forces among eight motors to prevent imbalance, and manages redundancy for fault tolerance. This multi-functionality handles the control complexity while maximizing the benefits of the overdetermined system.
4Ease of manufacture
If motors are connected in series with cable routing, then the system can be assembled, but additional hardware and complexity are required
Solution Approach 1:
The patent extracts and eliminates the cable routing hardware from the motor connection system. By using direct mechanical connections or alternative power transmission methods, it removes the complex cable management infrastructure while maintaining ease of assembly through modular motor-carriage units.
Data Source
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AI summary
A movement platform system comprising a base, a platform movable relative to said base and allowing an infinite yaw movement comprising an endless rail following a closed curve to which rail a number of motors is movably connected. The motors in turn are connected to the platform by means of a push-pull rod. The movement platform system is an overdetermined movement platform system, comprising one or more bases, a platform movable along 6 degrees of freedom and allowing an infinite yaw movement. To each endless rail of a set of two endless rails four or more motors are movably connected and wherein each motor is connected to the platform by means of the push-pull rod.