Cambridge Mechatronics Limited

Mark Easton

Andrew Benjamin Simpson Brown

Christopher Avery

Andrew Benjamin David Brown

Anthony Hooley

Robert John Leedham

Marc-Sebastian Scholz

Jonathan Morgan

David Charles William Richards

Paul Thomas Troughton

Angus Gavin Goudie

Irving Alexander Bienek

Paul Raymond Windle

Ian Edward Charles Rogers

Paul Windle

Damon Thomas Ryan

Chris Avery

A computer-implemented method driving an actuator component that drives movement of a movable part relative to a support structure, an image sensor fixed relative to the movable part or the support structure. The image sensor carries out CDS so as to read, offset in time by a sampling period, a reference signal and a light-sensing signal, and outputs a sync signal prior to CDS. The method comprises receiving the sync signal; generating PWM control signals at a PWM frequency substantially equal to an integer multiple of the reciprocal of the sampling period; during a sensing interval, suspending generating PWM control signals to drive the actuator component; and scheduling the sensing interval to start a time delay after receiving the sync signal, such that the sensing interval overlaps with both or neither of a duration of reading the reference signal and a substantially equal duration of reading the light-sensing signal by the image sensor.

Computer-implemented method of generating PWM control signals, and corresponding computer program, computer-readable storage medium and apparatus

A method of controlling power delivered to a shape memory alloy, SMA, actuator wire arrangement, wherein the arrangement comprises a plurality of SMA actuator wires, comprising: the steps of: applying, at a PWM frequency, to each of the SMA actuator wires during respective active periods a succession of voltage pulses; and applying, during a resistance measurement period, to one of the plurality of SMA actuator wires a resistance measurement current pulse, wherein the resistance measurement period corresponds to the respective active period of one of the plurality of SMA actuator wires.

Method and apparatus for controlling power delivered to an SMA actuator

Disclosed is a method of synchronising an image sensor with a PWM driver operable to drive an arrangement associated with the image sensor, wherein at least one synchronisation signal produced by the image sensor is used to reset the PWM driver and the at least one synchronisation signal is delayed before being used to reset the PWM driver such that the switching on or off of the at least one synchronisation signal occurs at a defined time in relation to a sensitive period of the image sensor's operation.

PWM synchronisation

There is provided a method of driving a shape memory alloy haptic assembly comprising an actuator comprising shape memory alloy that is arranged on actuation to provide a haptic effect, the method comprising supplying drive current to the actuator successively during a pre-heating period in which the temperature of the shape memory alloy is raised without causing the shape memory alloy to provide the haptic effect and during an actuation period in which the temperature of the shape memory alloy is raised so as to cause the shape memory alloy to provide the haptic effect. A shape memory alloy haptic assembly is also provided.

Control of SMA haptic assembly

Broadly speaking, embodiments of the present techniques provide techniques for delivering, when required, higher powers to SMA actuator wires by using a single controller/control circuit that implements pulse width modulation (PWM). Typically, when PWM is used to deliver power, the PWM frequency may be fixed, and power may be applied to each SMA actuator wire during each PWM cycle/period. The present techniques provide a method for delivering higher powers to SMA actuator wires (i.e. increasing the length of individual PWM pulses) without changing the duration of the PWM cycle/period. The present techniques also provide techniques for making accurate resistance measurements to determine position of a moveable component that is moved by the SMA actuator wires.

Methods for controlling power delivered to an SMA actuator

An apparatus is disclosed for measuring the resistance of a shape memory alloy, SMA, wire. The apparatus comprises: an SMA wire; a sense resistor connected in series with the SMA wire; a measurement circuit configured to perform a measurement indicative of the potential difference across at least the SMA wire; and a measurement switch between the SMA wire and the sense resistor. The measurement switch is configured to connect either to the measurement circuit such that the measurement circuit can perform the measurement or to a circuit that bypasses the sense resistor.

SMA wire resistance measurement

An SMA actuation apparatus comprises a support structure, a movable element movably supported on the support structure and an arrangement of three or more SMA actuator wires mechanically connected between the support structure and the movable element. The SMA actuator wires have an interconnection at the movable element that electrically connects the group of SMA actuator wires together. This avoids the need to make a separate electrical connection to the movable element.

Shape memory alloy actuation apparatus

Methods and apparatus are disclosed for actuating a shape-memory alloy actuator. An example method comprises a measurement phase, in which a voltage is applied across a bridge comprising a sense resistor to measure the resistance of the shape-memory alloy actuator, and a drive phase, in which a bypass unit is used to bypass the sense resistor while still driving current through the shape-memory alloy actuator in order to drive the shape-memory alloy actuator.

Drive circuit for actuating a shape-memory alloy actuator

The invention generally relates to a method and apparatus for taking an input signal, replicating it a number of times and modifying each of the replicas before routing them to respective output transducers such that a desired sound field is created. This sound field may comprise a directed beam, focussed beam or a simulated origin. In a first aspect, delays are added to sound channels to remove the effects of different travelling distances. In a second aspect, a delay is added to a video signal to account for the delays added to the sound channels. In a third aspect, different window functions are applied to each channel to give improved flexibility of use. In a fourth aspect, a smaller extent of transducers is used top output high frequencies than are used to output low frequencies. An array having a larger density of transducers near the centre is also provided. In a fifth aspect, a line of elongate transducers is provided to give good directivity in a plane. In a sixth aspect, sound beams are focussed in front or behind surfaces to give different beam widths and simulated origins. In a seventh aspect, a camera is used to indicate where sound is directed.

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Cambridge, United Kingdom

Mark Easton