Asphalt distributor with multispeed motor
AssigneeE.D. Etnyre & Co.
InventorsTyler Braun, Nick Frohmader
Life of this patent
Estimating the term…
Abstract
An asphalt distributor has a multispeed hydraulic motor mechanically driving an asphalt pump. The asphalt distributor has a controller for controlling the flow rate of asphalt being sprayed. The controller has a gain for controlling the flow rate. During a transition when the speed of the multispeed hydraulic motor changes, the gain has a value for the transition. Beneficially, the asphalt distributor has a wider than conventional asphalt spraying flowrate over which it provides a consistent spray. A method for controlling the flowrate involves adjusting, preferably dynamically, the value of the gain during the transition.
Claims20
An asphalt distributor for spraying asphalt onto the ground at a variable flowrate, the asphalt distributor comprising:
- a multispeed hydraulic motor having a first speed, a second speed, and an adjustable swashplate, the adjustable swashplate having a first position corresponding to the first speed and a second position corresponding to the second speed,
- an asphalt pump mechanically driven by the multispeed hydraulic motor, and
- a controller for controlling the flow rate of asphalt being sprayed, the controller having a gain for controlling the flow rate, a first mode in which the adjustable swashplate is in the first position, a second mode in which the adjustable swashplate is in the second position, and a transition mode for the movement of the adjustable swashplate between the first position and the second position, the first mode having a first flowrate range, the second mode having a second flowrate range different from the first flowrate range and overlapping at its lower end with the first flowrate range, the gain having a value for the first mode, a value for the second mode, and a value for the transition mode, the value for the transition mode being different from the value for the first speed and the value for the second speed, the controller entering into the transition mode when the motor switches between first speed and second speed.
A method of controlling the flow rate of an asphalt pump driven by a multispeed hydraulic motor during a transition for a speed change of the motor, the method comprising:
- changing the speed of the hydraulic motor by adjusting a swashplate in the hydraulic motor, and
- during the transition for the speed change, dynamically adjusting a proportional gain and an integral gain of a PI or PID controller controlling the flow rate during the transition as a function of the absolute relative error, the absolute relative error being the absolute difference between the flow rate and a desired flow rate divided by the desired flow rate, the adjustment of the proportional gain being different from adjustment of the integral gain.
Dependencies are inferred from the claim text.