Patent ID: 11952247
Assignee: AMAZON TECHNOLOGIES, INC.
Field: Transport (Mechanical engineering)
Classification: CPC B | IPC B

Claim 0:
1. A system comprising:
a drive wheel encoder that is associated with a drive wheel and is configured to determine a pallet jack velocity and a pallet jack acceleration of an electric pallet jack at a first time;
a load sensor that is configured to determine a load weight of a load, carried by the electric pallet jack, that is travelling at the pallet jack velocity and being accelerated by the pallet jack acceleration at the first time;
a drive motor that is configured to operate the drive wheel such that the load weight travels at the pallet jack velocity and is accelerated by the pallet jack acceleration at the first time;
an acceleration limit controller that is configured to:
receive, from the drive wheel encoder, a first indication of the pallet jack acceleration;
receive, from the load sensor, a second indication of the load weight;
determine, based on the load weight, an acceleration limit that provides a maximum acceleration for the drive wheel;
determine, based on the acceleration limit, that the pallet jack acceleration at the first time meets or exceeds the acceleration limit;
determine, based on the pallet jack acceleration meeting or exceeding the acceleration limit, a rate of power change for the drive motor, the rate of power change configured to limit a rate of acceleration for the load weight below the acceleration limit; and
determine, at a second time, that the pallet jack acceleration has been reduced below the acceleration limit; and

a velocity limit controller that is configured to:
receive, from the drive wheel encoder, a third indication of the pallet jack velocity;
receive, from the load sensor, the second indication of the load weight;
determine, based on the load weight, a velocity limit that provides a maximum velocity for the drive wheel;
determine, based on the velocity limit, that the pallet jack velocity at the first time meets or exceeds the velocity limit;
determine, based on the pallet jack velocity meeting or exceeding the velocity limit, a power limit for the drive motor, the power limit configured to limit a maximum velocity for the load weight; and
determine, at the second time, that the pallet jack velocity has been reduced below the velocity limit.