Haptic Rotary Input Using Worm Gear and Spring Force Feedback
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Solution Overview
Problem
Existing force generation input devices require large motors to transmit a sense of force to the operator, leading to increased device size.
Innovation Solution
The input device incorporates a worm gear, elastic members, and a controller to reduce the motor's torque requirement by using the elastic members' restoring force to provide a sense of force, allowing for a smaller device size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If torque is generated only by the motor to transmit sense of force to the operator, then the sense of force can be transmitted, but the motor size increases
Solution Approach 1:
The elastic member (spring) acts as a counterweight mechanism, generating restoring force in opposition to the movement member's displacement. This elastic restoring force supplements the motor's torque output, allowing the motor to be smaller while still providing adequate sense of force to the operator. The spring's mechanical energy storage and release compensates for the reduced motor torque.
Solution Approach 2:
The movement member serves as an intermediary element between the motor and the operator. It converts the motor's rotational torque into linear movement, which then interacts with the elastic member. This intermediary mechanism allows the system to leverage both motor torque and elastic restoring force, reducing the burden on the motor size while maintaining effective force transmission to the operator.
2Force
If large torque is generated by the motor to transmit sense of force, then the sense of force is sufficient, but the device size increases
Solution Approach 1:
The elastic member provides a counterbalancing force that reduces the total torque requirement from the motor. By leveraging the spring's restoring force, the system achieves sufficient sense of force transmission with a smaller motor, thereby reducing the overall device volume without compromising the operator's tactile feedback.
Solution Approach 2:
The system merges two force generation mechanisms: motor torque and elastic restoring force. The movement member integrates these two sources, combining the active motor output with the passive spring force. This combination allows the device to achieve adequate sense of force with reduced motor size, leading to compact overall dimensions.
3Force
If the worm gear is moved in the axial direction to act on the first gear, then a sense of force can be provided, but the structure becomes more complex
Solution Approach 1:
The movement member acts as an intermediary that converts rotational motion from the worm gear into linear axial movement. This mediator translates the complex three-dimensional interaction between the worm gear and first gear into a simpler linear displacement that directly engages the elastic member, thereby providing sense of force through a relatively straightforward mechanical pathway.
Solution Approach 2:
The transmission mechanism is segmented into distinct functional components: the worm gear for torque transmission, the movement member for motion conversion, and the elastic member for force generation. This segmentation allows each component to perform its specific function efficiently, reducing overall structural complexity while maintaining effective sense of force delivery to the operator.
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 enables a size-reduced input device that provides a sense of force to the operator while minimizing the motor's torque and size, improving space efficiency and usability.
Implementation Method 1
The elastic member is configured to generate urging force in a direction in which the movement of the movement member is suppressed
Implementation Method 2
The worm gear is configured to be rotated by the rotation shaft and attached to the rotation shaft so as to be movable in an axial direction of the rotation shaft
Data Source
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AI summary
A size-reduced input device is provided. An input device includes a base member, a motor, a rotation shaft, a worm gear, a first gear, a rotor, a movement member, an elastic member, a change amount detection unit, and a controller. The motor is attached to the base member. The rotation shaft is configured to be rotated by the motor. The worm gear is configured to be rotated by the rotation shaft and attached to the rotation shaft so as to be movable in an axial direction of the rotation shaft. The first gear is provided so as to be rotatable relative to the base member and engaged with the worm gear. The rotor is provided so as to be rotatable relative to the base member, includes a second gear engaged with the first gear, and is configured to undergo rotation operation performed by an operator. The movement member is configured to be moved as the worm gear is moved in the axial direction. The elastic member is configured to generate urging force in a direction in which the movement of the movement member is suppressed in accordance with a movement amount of the movement member. The change amount detection unit is configured to detect a change amount of a state that is changed in accordance with the movement of the movement member. The controller is configured to perform drive control for the motor to change a sense of force applied to the operator via the rotor in accordance with the change amount detected by the change amount detection unit.