Device for adjusting an operating variable of an engine
A mechanism for regulating an engine by using an actuator that is controlled in bang-bang mode, in which non-linearities are introduced in the control strategy in order to avoid putting excessive demand on an electric motor. The actuator is controlled by power supply pulses, which is a specific type of bang-bang control and, therefore, the actuator can receive a certain number of discrete commands. In one example, the actuator can receive two types of commands, for rotating in one direction and for rotating in the other direction.
1. An adjustment device for adjusting at least one operating variable of an engine as a function of a setpoint, the device comprising:
means for calculating a difference between a measurement of said at least one operating variable and said setpoint and if the calculated difference lies within a predetermined range then outputting an error value of zero otherwise outputting the error value equal to the calculated difference;
a first quantizer configured to quantize an amplitude of said error value;
means for determining a command duration as a function of a variation of said quantized error value amplitude;
a second quantizer configured to quantize said determined command duration; and
a sender unit configured to send a command of the bang-bang type in the form of a frame addressed to a port of an actuator configured to respond to a certain number of discrete commands, said command being a function of said quantized command duration and a sign of the variation of said quantized error value amplitude,
wherein said frame has a predetermined duration, and is subdivided cyclically into a predetermined number of pairs of first and second fields,
wherein each field is of a same field time duration,
wherein the first field corresponds to a first operation of the actuator in a first rotation direction and the second field corresponds to a second operation of the actuator in a second rotation direction,
wherein each field includes one of a first or second value for asserting or not asserting, respectively, said corresponding actuator operation for the corresponding field time duration, and
wherein a number of fields including the first value in each frame is a function of the quantized command duration.
2. The adjustment device according to claim 1 , further comprising means for defining said predetermined range.
3. An engine including:
at least one actuator configured to respond to a certain number of discrete commands; and
an adjustment device, coupled to the at least one actuator, configured to adjust at least one operating variable of an engine as a function of a setpoint, the adjustment device comprising:
means for calculating a difference between a measurement of said at least one operating variable and said setpoint and if the calculated difference lies within a predetermined range then outputting an error value set to zero otherwise outputting an error value equal to the calculated difference;
a first quantizer configured to quantize an amplitude of said error value;
means for determining a command duration as a function of a variation of said quantized error value amplitude;
a second quantizer configured to quantize said determined command duration; and
a sender unit configured to send a command of the bang-bang type in the form of a frame addressed to a port of said at least one actuator, said command being a function of said quantized command duration and a sign of the variation of said quantized error value amplitude,
wherein said frame has a predetermined duration, and is subdivided cyclically into a predetermined number of pairs of first and second fields,
wherein each field is of a same field time duration,
wherein the first field corresponds to a first operation of the at least one actuator in a first rotation direction and the second field corresponds to a second operation of the at least one actuator in a second rotation direction,
wherein each field includes one of a first or second value for asserting or not asserting, respectively, said corresponding actuator operation for the corresponding field time duration, and
wherein a number of fields including the first value in each frame is a function of the quantized command duration.
4. The engine according to claim 3 , wherein:
said at least one actuator is connected to said adjustment device by a bus via an interface, said interface comprising:
a port addressable by said adjustment device;
means for receiving, via said port, said frame; and
means for processing each of said fields independently and for sending or not sending a control signal to said at least one actuator as a function of the value contained in the field.
5. In a device for adjusting at least one operating variable of an engine as a function of a setpoint, a method of adjusting said at least one variable comprising:
receiving a measurement of said at least one engine variable at said device;
calculating a difference between said at least one operating variable measurement and said setpoint and if the calculated difference lies within a predetermined range then setting an error value to zero otherwise setting the error value equal to the calculated difference;
quantizing an amplitude of said error value;
determining a command duration as a function of a variation of said quantized error value amplitude;
quantizing said determined command duration; and
sending a command of the bang-bang type in the form of a frame addressed to a port of an actuator configured to respond to a certain number of discrete commands, said command being a function of said quantized command duration and a sign of the variation of said quantized error value amplitude,
wherein said frame has a predetermined duration, and is subdivided cyclically into a predetermined number of pairs of first and second fields,
wherein each field is of a same field time duration,
wherein the first field corresponds to a first operation of the actuator in a first rotation direction and the second field corresponds to a second operation of the actuator in a second rotation direction,
wherein each field includes one of a first or second value for asserting or not asserting, respectively, said corresponding actuator operation for the corresponding field time duration, and
wherein a number of fields including the first value in each frame is a function of the quantized command duration.
6. A non-transitory computer-readable medium on which there is recorded a computer program including instructions for implementing, on a computer, a method of adjusting at least one operating variable of an engine as a function of a setpoint, the method comprising:
receiving a measurement of said at least one operating variable;
calculating a difference between said received measurement and said setpoint and if the calculated difference lies within a predetermined range then setting an error value to zero otherwise setting the error value equal to the calculated difference;
quantizing an amplitude of said error value;
determining a command duration as a function of a variation of said quantized error value amplitude;
quantizing said determined command duration; and
sending a command of the bang-bang type in the form of a frame addressed to a port of an actuator configured to respond to a certain number of discrete commands, said command being a function of said quantized command duration and a sign of the variation of said quantized error value amplitude,
wherein said frame has a predetermined duration, and is subdivided cyclically into a predetermined number of pairs of first and second fields,
wherein each field is of a same field time duration,
wherein the first field corresponds to a first operation of the actuator in a first rotation direction and the second field corresponds to a second operation of the actuator in a second rotation direction,
wherein each field includes one of a first or second value for asserting or not asserting, respectively, said corresponding actuator operation for the corresponding field time duration, and
wherein a number of fields including the first value in each frame is a function of the quantized command duration.