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By wire control of braking and accelerationRelated Patent Categories: Motor Vehicles, Power, ElectricBy wire control of braking and acceleration description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070284160, By wire control of braking and acceleration. Brief Patent Description - Full Patent Description - Patent Application Claims
CROSS-REFERENCE TO RELATED APPLICATIONS [0001] This application claims the benefit of U.S. Provisional Application No. 60/550,885, filed Mar. 5, 2004. STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT [0002] Not Applicable BACKGROUND OF THE INVENTION [0003] 1. Field of the Invention [0004] The present invention is directed to surface cleaning equipment, and more particularly to a braking mechanism for surface cleaning equipment. [0005] 2. Background [0006] Surface maintenance vehicles and cleaning devices have a long history subject to gradual innovation and improvement toward improved and oftentimes automated performance in removing debris and contamination from floors. These vehicles and devices may be self-powered, towed, or pushed, and/or manually powered and may carry a human operator during cleaning operations. Such vehicles and devices include scrubbers, extractors, sweepers and vacuums, as well as combinations thereof, intended for cleaning, scrubbing, wiping and/or drying a portion of a substantially flat surface both indoors and outdoors. [0007] A class of surface maintenance vehicles, known as riders, may contain an operator that drives the vehicle, using controls functionally similar to those in an automobile, including a steering wheel, an accelerator pedal and a brake pedal. As in an automobile, the accelerator and brake speed up and slow down the vehicle, but because the motor in a rider vehicle is typically electric, the methods by which the accelerator and brake function are usually quite different from those in an automobile. [0008] The braking on a typical rider surface maintenance vehicle is generally accomplished in a mechanical manner, using a brake cable to transmit a force from the brake pedal to one or more brake pads. Although a mechanical brake assembly provides the operator with a comfortable "feel" for braking, it is relatively expensive. A significant cost savings would be realized if the mechanical braking assembly were eliminated. Note that for safety concerns, it is not feasible to eliminate the brake pedal on a rider surface maintenance vehicle. (In contrast, a walk-behind machine may function without an additional brake, because the speeds are much less and the machines may be much smaller.) [0009] For safety reasons, a rider surface maintenance vehicle usually has a mechanical brake, typically in the form of a spring-loaded caliper brake pad, which is often referred to as a parking brake, which may or may not share a mechanism with the mechanical brake described above. Generally, the parking brake may be activated electronically by a solenoid, so that if the current to the solenoid is shut off, as may occur during a failure mechanism, then the parking brake is engaged. The use of a solenoid-activated spring-loaded caliper brake as a parking brake is well-known in the art. In addition, it is common to engage the parking brake when the accelerator pedal is released, when the vehicle velocity drops below a threshold value. [0010] Accordingly, there exists a need for a braking mechanism that costs less than a mechanical assembly, but still provides the operator with a proper braking "feel", and stops the vehicle in the event of a malfunction. Thus, since most operators are already familiar with the feel of a mechanical braking system, designing an electrical system which proximates (mimics) that feel is highly desirable. BRIEF SUMMARY OF THE INVENTION [0011] An embodiment is a method of providing an electrical braking function through an electrical motor in a surface maintenance vehicle to mimic the function of a mechanical braking system, comprising the steps of: engaging a brake pedal to initiate braking function; sensing the position of the brake pedal and encoding the pedal position as an electronic signal; sensing the vehicle velocity; using said vehicle velocity and said signal, determining a desired machine deceleration rate to approximate the sensation of mechanical braking; determining the desired conductance applied in parallel to the motor to create a dynamic braking force from the motor; and re-adjusting the conductance in response to deceleration to mimic the feel of mechanical braking, whereby the vehicle is decelerated. [0012] A further embodiment is a method of providing an electrical braking function through an electrical motor in a surface maintenance vehicle to mimic the function of a mechanical braking system, comprising the steps of: engaging a brake pedal to initiate braking function; sensing the position of the brake pedal and encoding the pedal position as an electronic signal; sensing the vehicle velocity; using said vehicle velocity and said signal, determining a desired machine deceleration rate to approximate the sensation of mechanical braking; generating a series of pulses of frequency greater than the response frequency of the motor; within each pulse defining the desired duty cycle to create an effective conductance; applying the effective conductance in parallel with the motor to cause machine deceleration by dynamic braking; and iteratively checking vehicle velocity and brake pedal position and correspondingly altering duty cycle to respond to demand for greater or lesser braking. [0013] A further embodiment is a method of providing an electrical braking function through an electrical motor in a surface maintenance vehicle to mimic the function of a mechanical braking system, comprising the steps of: engaging a brake pedal to initiate braking function; sensing the position of the brake pedal and encoding the pedal position as an electronic signal; sensing the vehicle velocity; using said vehicle velocity and said signal, determining a desired machine deceleration rate to approximate the sensation of mechanical braking; generating an analog signal in response to the deceleration rate; applying a voltage in response to the analog signal to the motor to cause machine deceleration by dynamic braking; and iteratively checking vehicle velocity and brake pedal position and correspondingly altering the voltage to respond to demand for greater or lesser braking. [0014] A further embodiment is an electrically powered surface maintenance machine with dynamic braking capable of mimicking mechanical braking, comprising: an electric motor; a brake pedal having a position sensor; an encoder for converting the pedal position to an electrical pedal position signal; a machine velocity sensor; a braking rate controller capable of determining braking force tuned to approximate mechanical braking, in response to the electrical pedal position signal and the machine velocity; a converter to translate braking rate to an effective electrical load to be applied in parallel to the motor; an updater for iteratively checking the machine velocity and the pedal position and repeatedly adjusting the braking rate and thereby adjusting the effective electrical load applied in parallel to the motor. BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS [0015] FIG. 1 is a front view drawing of a pedal assembly. [0016] FIG. 2 is a rear view drawing of the pedal assembly of FIG. 1. [0017] FIG. 3 is an operations chart detailing the braking and acceleration of a rider surface maintenance vehicle. [0018] FIG. 4 is a plot of braking force versus time for various brake pedal positions. [0019] FIG. 5 is a plot of velocity versus time for various brake pedal positions, including a threshold velocity. Continue reading about By wire control of braking and acceleration... Full patent description for By wire control of braking and acceleration Brief Patent Description - Full Patent Description - Patent Application Claims Click on the above for other options relating to this By wire control of braking and acceleration patent application. ###  How KEYWORD MONITOR works... a FREE service from FreshPatents1. Sign up (takes 30 seconds). 2. Fill in the keywords to be monitored. 3. Each week you receive an email with patent applications related to your keywords. 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