Synchronized Parallel Rotating Masses for Directional Haptic Control
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Solution Overview
Problem
Existing vibration devices, particularly those using Eccentric Rotating Mass (ERM) and Linear Resonant Actuators (LRAs), struggle to provide directional haptic sensations due to their inability to sense and control the directionality of vibratory forces effectively.
Innovation Solution
The development of a synchronized array of vibration actuators in a network topology (SAVANT) architecture, which employs multiple configurations of vibration actuators, including linear motion vibration actuators and rotary vibration actuators, to generate a wide range of haptic sensations, including directional cues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a single ERM or LRA is used to produce vibration alerts, then the device can be kept simple and low cost, but the ability to provide directional haptic sensations is lost
Solution Approach 1:
The system divides the vibration generation function into multiple independent actuators (at least two ERMs or LRAs) that can be controlled separately. Each actuator can generate vibration along its own axis, and by coordinating their operation, the system can create directional haptic sensations that a single actuator cannot achieve.
Solution Approach 2:
The system transitions from single-axis vibration (one actuator) to multi-axis vibration (multiple actuators). By arranging actuators in different spatial orientations and controlling their phase relationships, the system expands the haptic output from one dimension to multiple dimensions, enabling directional control.
2Adaptability or versatility
If multiple ERMs are used with different rotating masses to provide directional feedback, then directional haptic sensations can be achieved, but the device complexity and power consumption increase
Solution Approach 1:
The system controls the operational parameters (amplitude, frequency, phase) of each actuator dynamically to achieve directional haptic effects. By adjusting these parameters in real-time based on the desired direction and intensity, the system can optimize power consumption while maintaining directional control capability.
Solution Approach 2:
The system uses periodic vibration patterns from multiple actuators to create directional sensations. By coordinating the timing and phase of periodic vibrations from different actuators, the system can direct haptic energy toward specific directions, improving efficiency compared to continuous operation of all actuators at full power.
3Ease of operation
If ERM actuators are used to generate centripetal forces, then vibration can be produced, but the directionality of the vibratory forces cannot be sensed or controlled
Solution Approach 1:
The system incorporates sensors (such as accelerometers or gyroscopes) to detect the actual vibration direction and magnitude. This feedback information is used to adjust the control signals to the actuators, enabling closed-loop control of vibration directionality. The system can sense the resulting haptic output and correct deviations from the desired direction.
Solution Approach 2:
The system uses asymmetric actuator configurations or asymmetric activation patterns to create directional haptic cues. By activating actuators in specific combinations with different amplitudes and phases, the system can generate asymmetric vibration patterns that provide clear directional information to the user.
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 approach enables the creation of human-perceptible directional haptic sensations, improving the controllability and power efficiency of vibration devices, and allowing for the generation of both directional and non-directional vibration waveforms.
Implementation Method 1
ERM actuators generate centripetal forces that rotate in a plane, and generally the direction of vibration (that is to say, the instantaneous direction of the rotating centripetal force vector) cannot be not sensed in haptic applications
Implementation Method 2
ERM actuators generate centripetal forces that rotate in a plane
Implementation Method 3
vibration actuators are typically the smallest and lowest cost method for generating haptic sensations
Data Source
AI summary
The technology provides for generating pure torque vibrations using a synchronized pair of rotating masses arranged in parallel. Each mass is statically balanced but dynamically imbalanced, producing a torque vibration substantially without generating a net translational force when rotated at a constant angular velocity. By rigidly coupling motors and adjusting the relative phase angle between their shafts, the combined torque output can be varied continuously from approximately zero amplitude to a maximum amplitude. The approach supports co-rotating and counter-rotating modes at the same or differing angular velocities, enabling effects such as torque beating (arising from slightly different co-rotating speeds) and torque spinning (arising from counter-rotating shafts at differing angular velocities). These operational modes effectively decouple vibration amplitude from frequency, offering versatile control over torque-based vibration characteristics. The disclosed technology is applicable to products including handheld or wearable haptic devices, game controllers, personal grooming devices, industrial vibrators, and automotive applications.