Continuum Robot Control via Multi-Wire Force Estimation
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Solution Overview
Problem
Conventional wire-driven continuum robots face challenges in detecting external forces during contact with objects, leading to potential damage due to excessive loads, as existing methods that compare load on single wires with threshold values are inadequate in distinguishing between driving force and external forces, thereby limiting the operational range and increasing the risk of damage.
Innovation Solution
A continuum robot control apparatus that estimates external forces applied to the bendable portion based on tensile forces in multiple wires and adjusts driving control accordingly, using an external force estimating unit and driving control unit to manage wire driving forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a threshold value is lowered to detect external forces, then damage suppression is improved, but the operational range is narrowed
Solution Approach 1:
The patent segments the force detection function across multiple wires (at least two wires) rather than relying on a single wire. By comparing tensile forces from multiple wires, the system can distinguish external contact forces from normal driving forces, enabling reliable damage suppression without unnecessarily limiting the operational range.
Solution Approach 2:
The patent implements a feedback mechanism where the control unit continuously monitors tensile forces from multiple wires and adjusts driving commands based on comparisons between wires. When the control unit detects that a driven wire's tensile force exceeds another wire's tensile force by a predetermined threshold, it interprets this as external contact and modifies driving commands accordingly, enabling adaptive force management.
2Adaptability or versatility
If a threshold value is increased to maintain operational range, then adaptability is improved, but damage detection capability deteriorates
Solution Approach 1:
The patent segments the force detection function across multiple wires (at least two wires) rather than relying on a single wire. By comparing tensile forces from multiple wires, the system can distinguish external contact forces from normal driving forces, enabling reliable damage suppression without unnecessarily limiting the operational range.
Solution Approach 2:
The patent uses the relative comparison between multiple wires as an intermediary mechanism to detect external forces. Instead of using a fixed threshold on a single wire, the system uses the difference in tensile forces between wires as an intermediate indicator of external contact, enabling more accurate detection across varying operational conditions.
3Device complexity
If single wire load detection is used, then device complexity is reduced, but measurement precision deteriorates
Solution Approach 1:
The patent segments the force detection function across multiple wires (at least two wires) rather than relying on a single wire. By comparing tensile forces from multiple wires, the system can distinguish external contact forces from normal driving forces, enabling reliable damage suppression without unnecessarily limiting the operational range.
Data Source
AI summary
The present invention provides a mechanism which can avoid narrowing of a range in which a continuum robot can be driven and suppress damage to the continuum robot and an object. A continuum robot control apparatus controlling an operation of a continuum robot having a bendable portion bending in response to driving of at least some of a plurality of wires includes an external force estimating unit configured to estimate an external force applied to the bendable portion based on compressive/tensile forces applied to two or more wires of the plurality of wires, and a driving control unit configured to control driving of the wires to be driven based on the external force estimated by the external force estimating unit.