Haptic Actuator with Pre-compressed Spring for Immediate Feedback
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Solution Overview
Problem
Existing haptic feedback control modules in automotive systems, such as touch interface modules, face challenges in providing perceptible and efficient haptic feedback due to inadequate initial oscillations and suboptimal energy conversion, leading to delayed user feedback and reduced haptic perception.
Innovation Solution
An actuator with increased spring stiffness, utilizing a damper made of elastomer and helical thrust springs, and a method of controlling the electromagnet to separate and propel the movable core against a contact wall with defined current polarizations, enhancing the percussive haptic feedback felt by the user.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the electromagnet is supplied with alternating signals to generate vibrations, then the mobile core oscillates between extreme positions, but the first oscillations are not perceptible by the user and delay haptic feedback
Solution Approach 1:
The patent applies preliminary action by pre-compressing the elastic element before activating the electromagnet. This stores potential energy in advance, enabling the mobile core to be rapidly propelled against the contact wall immediately when needed, eliminating delayed oscillations and providing immediate perceptible haptic feedback to the user.
Solution Approach 2:
The patent uses periodic action by controlling the electromagnet with alternating signals that periodically activate and deactivate. This creates repeated cycles of mobile core propulsion against the contact wall, generating rhythmic percussive vibrations that are easily perceptible to the user while maintaining fast response timing.
2Power
If the mobile core is driven by the stator with alternating signals, then translational displacement amplitude increases to maximum, but the ratio between electrical energy supplied and mechanical energy felt by the user is not optimal
Solution Approach 1:
The patent applies beforehand cushioning by introducing a damper between the mobile core and the contact wall. This damper absorbs and dissipates excess kinetic energy that would otherwise be wasted, converting it into useful percussive vibrations. The elastic element also stores and releases energy efficiently, improving the conversion ratio from electrical to mechanical energy felt by the user.
3Force
If a frank and hard-hitting haptic feedback is desired, then the haptic feeling is improved, but the existing actuator design does not provide sufficient percussive impact
Solution Approach 1:
The patent applies the counterweight principle by using the elastic element to store and release energy in opposition to the electromagnetic force. This creates a rebound effect that amplifies the percussive impact when the mobile core strikes the contact wall, generating stronger haptic feedback force while maintaining ease of operation through the passive elastic mechanism.
Solution Approach 2:
The patent directly applies mechanical vibration by designing the actuator to generate percussive vibrations through the mobile core's repeated impact against the contact wall. The damper and elastic element are specifically configured to optimize these vibrations, producing frank and hard-hitting haptic feedback that is easily perceived by 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
The solution provides faster, more pronounced, and better-perceived haptic feedback, improving user interaction by ensuring timely and effective communication of command execution, reducing cognitive load during vehicle operation.
Implementation Method 1
a stator having an electromagnet and configured to be able to drive the mobile core according to a reciprocating translational movement
Implementation Method 2
at least one elastic element arranged between the mobile core and the frame and configured to be able to maintain the mobile core in each of its extreme positions
Implementation Method 3
a damper arranged between the mobile core and the frame and configured to be able to damp oscillations of the mobile core
Implementation Method 4
By an inertial effect, the movement of the mobile core by the stator is transmitted to the frame which in turn transmits the vibration movement to a touch surface
Data Source
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Figure 3
Figure 4~5
AI summary
The invention relates to an actuator (7) which comprises: a frame (11) intended for being in contact with the tactile interface via a contact wall (13) so as to transmit haptic feedback to the tactile surface; a stator (15) connected to the frame (11); a movable core (19) connected via at least one resilient element to the frame (11) and intended for being moved by the stator (15) so as to generate the haptic feedback; an electromagnet (17) and at least one permanent magnet (20), one of which is supported by the stator and the other by the movable core (19). The actuator (7) also comprises a shock absorber (23) arranged between the movable core (19) and the contact wall (13), and said resilient element is sized so that, when the electromagnet is not powered, the movable core (19) applies a bearing force towards the contact wall (13) and, when the electromagnet is powered according to a predetermined polarisation, the movable core (19) moves away from the contact wall (13).