Laundry treating appliance and methods of operation
A method of operating a laundry treating appliance includes controlling rotation of a drum during a cycle of operation by a controller communicably coupled to a motor, sending an excitation signal to a controller that randomly fluctuates an acceleration command to affect acceleration of the motor, determining, by the controller during excitation, one or more inputs sensed from the motor, and estimating with a parameter estimator parameter values of a laundry load in the drum based on the inputs. The cycle of operation can then be adjusted based on the estimated parameter values of the laundry load.
1. A method of operating a laundry treating appliance having a drum at least partially defining a treating chamber for receiving a laundry load for treatment according to a cycle of operation, and a motor operably coupled with the drum to rotate the drum, the method comprising:
controlling rotation of the drum during the cycle of operation by a controller communicably coupled to the motor;
sending an excitation signal to the controller wherein the excitation signal randomly fluctuates an acceleration command to effect acceleration of the motor;
determining, by the controller during excitation, at least one input sensed from the motor;
estimating with a parameter estimator parameter values of the laundry load in the drum based on the at least one input; and
adjusting the cycle of operation based on the estimated parameter values of the laundry load.
2. The method of claim 1 wherein the excitation signal is derived from a uniform white noise sequence.
3. The method of claim 2 wherein the uniform white noise sequence is generated by a logic for a fundamental period comprising:
{dot over (ω)}* Exc ←A WN *U[− 1,1]
where A WN is an amplitude, {acute over (ω)}* Exc is the excitation signal, and U[a,b] denotes a uniform random number in an interval [a,b].
4. The method of claim 2 wherein the excitation signal is tunable in amplitude or duration.
5. The method of claim 1 wherein the excitation signal is derived from a pseudo-random binary sequence.
6. The method of claim 5 wherein the pseudo-random binary sequence is generated by a logic comprising:
Initialize {acute over (ω)}* Exc =A PRBS ,T Exc =U[T min ,T PRBS ];
Repeat:
Wait T Exc , Wait until hold time has expired;
{acute over (ω)}* Exc ←−{acute over (ω)}* Exc , Switch to the other acceleration level;
T Exc ←U[T min , T PRBS ], Draw a new random time;
where {acute over (ω)}* Exc is the excitation signal, T Exc is an excitation time, U is a uniform random number, T PRBS is a maximum hold time, and A PRBS is an amplitude of the sequence, T min is a fixed parameter representing a minimum hold time of the sequence.
7. The method of claim 5 wherein the excitation signal is tunable in duration and the sequence alternates between two fixed acceleration levels.
8. The method of claim 1 wherein estimating the parameter values utilizes a model comprising:
T=J{dot over (ω)}+bω+c+A sin(α+β)
wherein T=torque, J=inertia, {dot over (ω)}=acceleration of the drum, ω=rotational speed of the drum, b=viscous friction, c=coulomb friction, A=amplitude of a basket speed first harmonic torque disturbance, which may be a function of an unbalance mass, surface tilt angle, gravitational acceleration, unbalance mass position, and basket speed, α=rotational position of the drum, and β=rotational position of an imbalance of the laundry load relative to the rotational position of the drum.
9. The method of claim 1 wherein the at least one input is one of a torque of the motor, an acceleration of the drum, a rotational speed of the drum, or an angular position of the drum.