Host Force Feedback Externally-Triggered Periodic Torque

Produces a periodic torque effect on a game controller on the host that is triggered by an input signal.

Library

Description

The Host Force Feedback Externally-Triggered Periodic Torque block produces a periodic torque on the host game controller in response to the rising edge of the Trigger input. The block may be configured to stop the effect on the falling edge of the trigger signal. The periodic torque may take the form of a square wave, sine wave, triangle wave, upward-traveling sawtooth wave or downward-traveling sawtooth wave.

The Tx, Ty and Tz inputs define a torque vector whose magnitude and direction determines the amplitude and direction of the periodic torque applied by the game controller. The amplitude and direction of this torque are updated every time the trigger occurs, according to the inputs to the block. The parameters of the block determine the temporal characteristics of the effect, such as the duration and envelope. A Host Force Feedback Game Controller block must be present in the model to configure the game controller.

Limitations

Unused axes

Unused axes should be left unconnected or connected to the

Level of support

Not all force feedback game controllers will support a condition torque effect that is triggered by a signal. If externally-triggered condition torque effects are supported, a game controller may not support all the axes or features of this block.

Input Ports

Trigger

The signal used to start or stop the effect. Refer to the Trigger mode parameter for details.

Tx

The normalized amplitude of the torque to apply about the X axis (-1.0=-maximum, 0.0=no torque, 1.0=+maximum). The positive X direction is from left to right. If this axis is unused, connect it to a

Ty

The normalized amplitude of the torque to apply about the Y axis (-1.0=-maximum, 0.0=no torque, 1.0=+maximum). The positive Y direction is from left to right. If this axis is unused, connect it to a

Tz

The normalized amplitude of the torque to apply about the Z axis (-1.0=-maximum, 0.0=no torque, 1.0=+maximum). The positive Z direction is from left to right. If this axis is unused, connect it to a

offset

An offset by which to bias the waveform from zero. For example, for a sine wave, the magnitude of the output torque will be equal to:

offset + amplitude * sin(2π*time/period + phase)

phase

The phase in radians of the periodic waveform. See description of the offset input for an example.

period

The period in seconds of the periodic waveform. See description of the offset input for an example.

Output Ports

This block has no output ports.

Parameters and Dialog Box

Controller name

The identity of the associated Host Force Feedback Game Controller block. The Host Force Feedback Externally-Triggered Periodic Torque block must be associated with a Host Force Feedback Game Controller block.

Effect type (tunable offline)

The type of periodic waveform to generate. The supported types are a square wave, sine wave, triangle wave, upward-traveling sawtooth wave and downward-traveling sawtooth wave.

Trigger mode

The function of the trigger input to the block. If this parameter is set to "Start" then a rising edge at the trigger input will start the effect. The effect will stop when the effect duration has expired. A falling edge at the trigger input will be ignored.

If this parameter is set to "Start/Stop" then a rising edge at the trigger input will also start the effect. However, the effect will stop when the effect duration has expired or a falling edge is seen at the trigger input.

Effect gain (tunable online)

A normalized gain to apply to the effect. The torques are scaled by this gain before being applied to the device. The gain must be a fraction between 0 and 1 inclusive. This parameter is useful for scaling effects for a different game controller.

Number of iterations (tunable online)

The number of times to play the effect in sequence. The envelope is re-articulated with each iteration. If this value is -1 then the effect is played indefinitely.

Envelope attack level (tunable online)

The normalized amplitude (0.0=no torque, 1.0=maximum) of the torque at the beginning of playback.

Envelope attack time (tunable online)

The amount of time in seconds for the amplitude of the effect to ramp linearly from the attack level to the sustain level. The sustain level is the amplitude of the torque specified at the block inputs. This parameter may be zero.

Envelope fade level (tunable online)

The normalized amplitude (0.0=no torque, 1.0=maximum) of the torque at the end of playback.

Envelope fade time (tunable online)

The amount of time in seconds for the amplitude of the effect to ramp linearly from the sustain level to the fade level. The sustain level is the amplitude of the torque specified at the block inputs. This parameter may be zero.

Effect duration (tunable online)

The total duration of the effect in seconds. It should be larger than sum of the envelope's attack and fade times. The difference between the effect duration and the sum of the attack and fade times determines the time for which the sustain level is maintained.

Delay in starting the effect (tunable online)

The time in seconds to delay starting the effect after the trigger has occurred.

Effect sampling period (tunable online)

The sampling period of the effect in seconds. This parameter determines the sampling period of the effect on the device itself. It is not related to the sample time of this block, or to the period of the effect waveform. It is the period at which the magnitude of the effect is updated by the device. If this value is zero, the default sampling period is used.

Targets

See Also

• Devices on the Host PC

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