Direct-Drive Mechanical Arm Assembly for High-Fidelity Force Feedback

Solution Overview

Problem

Existing control input devices for teleoperated systems, such as surgical robots, often rely on gear reduction mechanisms to amplify motor torque, which introduces additional friction and complexity, compromising the fidelity of force feedback and increasing costs.

Innovation Solution

A direct drive mechanical arm assembly is implemented, where motors are coupled directly to arm members without torque scaling, using a 1:1 drive ratio, eliminating the need for gear mechanisms and reducing friction and inertia, allowing for more precise and cost-effective force transmission.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If gear reduction mechanisms are used to amplify motor torque, then the output torque is increased, but friction and assembly complexity increase

Engineering Contradiction:

Improveoutput torqueVSAvoidassembly complexity

Core Design Contradiction:

ForceVSDevice complexity

Solution Approach 1:

The patent removes the gear reduction mechanism entirely from the system. Instead of using gears to amplify torque, the invention uses a direct drive configuration where the motor is coupled directly to the arm member, extracting the problematic intermediate transmission component that introduced friction and complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical gear reduction system with a direct electromagnetic coupling. The motor's rotor is directly coupled to the arm member, eliminating the need for mechanical gear transmission and its associated friction, wear, and complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Force

If gear reduction mechanisms are used to amplify motor torque, then the output torque is increased, but friction increases

Engineering Contradiction:

Improveoutput torqueVSAvoidfriction

Core Design Contradiction:

ForceVSObject-affected harmful factors

Solution Approach 1:

The patent removes the gear reduction mechanism entirely from the system. Instead of using gears to amplify torque, the invention uses a direct drive configuration where the motor is coupled directly to the arm member, extracting the problematic intermediate transmission component that introduced friction and complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical gear reduction system with a direct electromagnetic coupling. The motor's rotor is directly coupled to the arm member, eliminating the need for mechanical gear transmission and its associated friction, wear, and complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Force

If gear reduction mechanisms are used to scale up motor torque, then the output torque is increased, but torque disturbances and friction are amplified

Engineering Contradiction:

Improveoutput torqueVSAvoidtorque smoothness

Core Design Contradiction:

ForceVSReliability

Solution Approach 1:

The patent removes the gear reduction mechanism entirely from the system. Instead of using gears to amplify torque, the invention uses a direct drive configuration where the motor is coupled directly to the arm member, extracting the problematic intermediate transmission component that introduced friction and complexity.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the mechanical gear reduction system with a direct electromagnetic coupling. The motor's rotor is directly coupled to the arm member, eliminating the need for mechanical gear transmission and its associated friction, wear, and complexity.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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

This configuration enhances the fidelity of force feedback, reduces assembly complexity and costs, and allows for a more compact design with balanced weight distribution, improving the overall performance and usability of control input devices in teleoperated systems.

Implementation Method 1

a first motor coupled to the base member, the first motor including a first drive shaft rotatable about the first axis and coupled to the first arm member

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentUS20210145530A1Direct drive for mechanical arm assembly

Publication Date: 2021.05.20 INTUITIVE SURGICAL OPERATIONS INC

AI summary

Implementations relate to a direct drive for a mechanical arm assembly. In some implementations, a mechanical arm assembly includes a base member, a first arm member rotatably coupled to the base member at a first portion of the first arm member, and a second arm member having a first portion rotatably coupled to a second portion of the first arm member. The first arm member is rotatable with respect to the base member about a first axis, and the second arm member is rotatable with respect to the first arm member about a second axis. A first motor coupled to the base member, the first motor including a first drive shaft rotatable about the first axis and coupled to the first arm member. A grip member is coupled to a second portion of the second arm member.