Handheld Robot Manipulator Interface for Low-Strain Trigger Control

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Solution Overview

Problem

Existing user interface devices for robotic systems, such as master-slave manipulators, are tiring to use due to lack of forearm support, leading to muscle strain and discomfort during prolonged use.

Innovation Solution

A user interface device designed to be gripped by a single hand, featuring a motor and gearbox located within the grip portion, with a trigger that rotates relative to the body and is driven by a drive shaft, and equipped with position and force sensors to provide ergonomic comfort and precise control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If a traditional master-slave manipulator controller with gimbal system and parallelogram system is used, then six degrees of freedom movement control is achieved, but the device becomes heavy and tiring to use without forearm support

Engineering Contradiction:
Improvedegrees of freedom controlVSAvoidcontroller weight
Core Design Contradiction:
Adaptability or versatilityVSWeight of moving object

Solution Approach 1:

The patent extracts and removes the complex gimbal system and parallelogram system from the controller design. Instead of using these mechanical systems to achieve six degrees of freedom, the invention uses a simplified trigger mechanism with spring bias and electrical sensors to detect position and force, thereby eliminating unnecessary mechanical complexity and weight while maintaining control functionality.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical gimbal and parallelogram systems with an electrical sensing system. The trigger position is detected using electrical sensors (such as potentiometers or Hall effect sensors) rather than mechanical linkages, and force feedback is provided through a spring mechanism coupled with electrical actuation, substituting complex mechanical systems with simpler electro-mechanical systems.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Ease of operation

If forearm rest is provided to reduce muscle strain, then ergonomic comfort is improved, but the working positions the user can adopt are restricted

Engineering Contradiction:
Improveergonomic comfortVSAvoidworking positions
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The patent employs a spring-loaded trigger mechanism that provides force feedback to the user's finger. The spring is pre-loaded to provide a counterbalancing force that reduces the effort required to move the trigger, thereby reducing muscle strain in the user's finger and hand without requiring external forearm support structures that would restrict working positions.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

3Ease of manufacture

If motor and gearbox are located within the grip portion, then assembly costs and weight are reduced, but the trigger mechanism becomes more complex

Engineering Contradiction:
Improveassembly costVSAvoidtrigger mechanism complexity
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The patent merges the motor and gearbox into a single integrated unit located within the grip portion of the controller. This consolidation reduces the number of separate components, simplifies assembly procedures, and reduces overall weight. The integrated motor-gearbox assembly directly drives the trigger mechanism, eliminating the need for separate mounting brackets and alignment procedures.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent nests the gearbox within the motor housing or integrates the gearbox gears within the motor assembly. This nesting arrangement allows the gearbox to be housed within the same space as the motor, reducing the overall volume occupied by the drive mechanism and allowing it to be contained within the grip portion of the controller without increasing external dimensions.

Inventive Principle:
Principle #7Nested doll (Nesting)

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

The device provides improved ergonomic comfort by reducing wrist and forearm strain, allowing precise control and efficient force feedback, enhancing usability and reducing the weight and assembly costs.

Implementation Method 1

The drive mechanism comprises motor. The motor is arranged for applying force to the trigger.

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

The user interface device may comprise a position sensor for sensing the position of the trigger relative to the body.

Methodology Applied
Scientific EffectPosition sensing:

Implementation Method 3

The user interface device may comprise a force sensor for sensing force applied between the trigger and the body.

Methodology Applied
Scientific EffectForce sensing:

Implementation Method 4

The trigger is arranged to rotate relative to the body about a rotation axis. The rotation axis is coincident with the rotation axis of the motor.

Methodology Applied
Scientific EffectRotational motion:

Data Source

PatentEP3516475B1User interface device
Publication Date: 2025.07.09 CMR SURGICAL LTD
  • EP3516475B1 patent drawingFigure 1~2
  • EP3516475B1 patent drawingFigure 3a~3c
  • EP3516475B1 patent drawingFigure 3d~3f

AI summary

A user interface device for controlling a robot manipulator having an end effector comprising at least one movable element, the user interface device comprising: a body for being held by a user, the body comprising an elongate grip portion configured to be gripped by one or more of a user's second to fourth fingers; a trigger extending transversely to the direction of elongation of the grip portion, thetrigger being supported by the body so as to be capable of rotating relative to the body about a rotation axis passing through the grip portion; and a drive mechanism at least partially housed in the grip portion, the drive mechanism being coupled to the trigger for applying a torque to the trigger.