Data processing: vehicles – navigation – and relative location – Vehicle control – guidance – operation – or indication – Indication or control of braking – acceleration – or deceleration
Reexamination Certificate
1999-12-30
2001-11-27
Cuchlinski, Jr., William A. (Department: 3661)
Data processing: vehicles, navigation, and relative location
Vehicle control, guidance, operation, or indication
Indication or control of braking, acceleration, or deceleration
C180S065100, C180S065600, C180S065700
Reexamination Certificate
active
06324464
ABSTRACT:
BACKGROUND OF THE INVENTION
The invention relates to regulating the speed of an electric motorcycle.
Electric motorcycles are generally driven by an electric motor powered by a battery. The battery requires periodic charging to replenish its energy reserves when its stored electric energy is depleted. The time between successive battery charging sessions is referred to as a charging cycle. The efficiency of an electric motorcycle is generally determined by the distance it travels in one charging cycle.
The energy efficiency of an electric motorcycle depends on the weight, speed, and acceleration of the motorcycle. High-speed travel generally consumes more energy per unit of distance traveled because of increased frictional losses. Rapid acceleration and deceleration also reduce the energy efficiency. Efforts to improve efficiency include making lighter electric motorcycles, designing light high-capacity batteries, and reducing the vehicle drag. However, many of these approaches for improving efficiency significantly increase the cost of the motorcycle.
Many electric motorcycles include a rotatable mechanism (e.g., lever) mounted on the end of the handlebar of the motorcycle that the rider rotates to change the motorcycle's speed. The more the mechanism is rotated the greater the speed. The motorcycle's response to rotation of the mechanism varies depending on a number of factors, including the slope of the motorcycle's path and the weight of the rider.
SUMMARY OF THE INVENTION
The invention features a system for regulating the speed of a motorcycle, of the type powered by an electric motor and a battery. In one general aspect of the invention, the system includes a command module that determines a desired speed of the motor and a controller which controls the electric motor based on both the desired speed and an actual speed of the motor, determined, for example, by a speed sensor.
In essence the system provides a closed-loop controller that, contrary to conventional open-loop schemes, controls the motor so that the actual speed is a better approximation of the desired speed.
Embodiments of the invention may include one or more of the following features. The controller controls the motor in response to the difference between the desired speed and the actual speed so as to minimize the difference. The controller controls the speed and acceleration of the motorcycle so as to increase traveling distance per charging cycle.
The motorcycle has an actuator (e.g., a lever) for generating a target speed signal representing a target speed of the motorcycle. The command module receives the target speed signal.
The system further includes an energy sensor that generates an energy signal representing an amount of energy stored in the battery and a desired distance setter which generates a desired traveling distance signal representing a desired traveling distance. The command module generates the desired speed signal based on the energy signal and the desired traveling distance signal. The command module also computes a maximum speed that can be maintained if the motorcycle is to travel the desired distance on the available amount of battery energy. The desired speed signal is based on the maximum speed when the target speed signal is above the maximum speed.
The command module includes a memory for storing a lookup table. The lookup table is used to determine the maximum speed that can be maintained if the motorcycle is to travel the desired distance on the available amount of battery energy. Alternatively, a computer program computes the maximum speed based on a formula. The maximum speed is based on properties of the motorcycle such as its motor properties. The command module determines the maximum speed based on experimental data on the motorcycle energy consumption at various speeds. Thus, the command module reduces the likelihood that the battery energy will run out before the motorcycle travels the desired distance.
In certain embodiments, the system further includes a range sensor that senses a range distance between the motorcycle and an object in its path, such as an automobile. A safe speed, representative of a maximum actual speed that the motorcycle can attain without danger of colliding with the object, is determined by the command module based on the range distance. The system further includes a display for displaying the safe speed to a motorcycle rider thereby providing a guideline for setting the target speed. The command module is configured such that the desired speed signal is based on the safe speed when the target speed is above the safe speed. The command module is configured such that when the target speed is greater than the safe speed, the desired speed is based on a product of the target speed and a scaling parameter. The scaling parameter is based on the safe speed. For example, the scaling parameter may be the ratio of the safe speed to a maximum attainable motorcycle speed. The command module includes a memory for storing a lookup table used to derive the safe speed. The command module includes a computer program for computing the safe speed based on a mathematical formula. The command module derives the safe speed based on experimental data on the braking distance of the motorcycle at various speed. The command module derives the safe speed based on properties of the motorcycle, such as its braking properties. Thus the system reduces the likelihood of collision with an obstacle, such as an automobile, that may be in the motorcycle's path.
Additionally, the system includes an element for setting a motorcycle rider's cruise speed. The command module is configured such when the cruise speed element is activated, the desired speed is based on the cruise speed.
The controller includes a current driver for driving the motor. The current driver increases the maneuverability of the motorcycle by providing direct control of the motor torque.
The command module generates the desired speed signal based on a digital signal from an analog to digital converter. The actual speed signal is an analog signal which is converted by an analog-to-digital converter. The controller controls the motor using a command signal which is converted by a digital-to-analog converter. The speed sensor may include a tachometer. At least part of the system may be implemented in software that runs on a processor. The controller and the command module may both be implemented by software that runs on the same processor or different processors.
In another general aspect of the invention, an apparatus for charging an electric motorcycle battery, used with an electric motorcycle having a wheel, includes a magnet and a conducting coil located within the magnetic field of the magnet. The conducting coil has a first end electrically connected to a first terminal of the battery and a second end electronically connected to a second terminal of the battery. At least one of the magnet and the conducting coil is mechanically coupled to the wheel so that rotation of the wheel results in relative motion between the coil and the magnet.
Embodiments of the invention may include one or more of the following. Either the coil or the magnet may be mechanically coupled to the wheel. The battery is an auxiliary battery for accessory lighting of the motorcycle (e.g., head, tail, and turn signal lights).
Other advantages and features of the invention will become apparent from the following description and the claims.
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Lee Der-Tsai
Wu Chi-haur
Academia Sinica
Cuchlinski Jr. William A.
Fish & Richardson P.C.
Marc-Coleman Marthe Y.
LandOfFree
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