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REMOTE CONTROL LAWN MOWER

The invention relates to remote control lawn mowers using a hand held transmitter and a

remote control lawn mower unit.

The present invention is intended to minimize the physical labor effort in cutting the lawn

but eliminating the need to follow behind the mower. This would be helpful to elderly people

who maintain their lawns or to those with disabilities where physical exertion is not

recommended.

SUMMARY OF THE INVENTION

The present invention has a proportional front steering control, forward/reverse speed

control, a gyro for fast straight line cuts, and a gas engine (typical rating being about 4.5 to 7.5

HP) to cut the grass and charge the batteries. All heavy components such as batteries, gas engine

should be engineered for optimum balanced in all its proportions. The batteries can be charged

from a household outlet or from the gas engine itself when operating; it is a hybrid on its own.

The steering control (the heart of the system) has an excellence fast response; it is a fast, safe,

energy efficient, effortless remote control lawn mover that does not compromise speed or power

to cut the lawn. All these unique features make the present invention a lawn mover that one

controls and enjoys.

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BRIEF DESCRIPTION OF THE DRAWINGS

In the accompanying drawings:

Fig. 1 is a drawing depicting a 3-D model of the hand held transmitter portion of the

invention;

Fig. 2 is a representational 3-D Model depicting the typical mechanical and electrical

components of the present invention using a perspective view of the present invention;

Fig. 2b is a representational 3-D Model depicting the mechanical and electrical

components of in a different configuration of the invention.

Fig. 3 illustrates the functional components of the controller box portion;

Fig. 4 illustrates a typical example of a feedback control system for the steering motor

portion of the present invention;

Fig. 5a illustrates an example of a placement of the potentiometer, steering motor, and

gear box;

Fig. 5b depicts a rear view and schematic of the Fig. 5a components;

Fig. 6 illustrates an example of the feedback control system for the speed control;

Fig. 7 illustrates typical components of the Speed motor, gear box, and differential;

Fig. 8 illustrates an example of alternator schematics;

Fig. 9 illustrates a typical design configuration for the pulley, shaft and belt design for

charging the batteries;

Fig. 10 is a detail schematics showing an example of all electrical and mechanical

components;

Figs. 11a-11b are pictorial views of the present invention actually built and operable.

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DETAILED DESCRIPTION OF THE DRAWINGS

Referring now to the drawings, the drawings disclose a typical application or example of

the present invention.

Fig. 1 is a representation of the Radio Frequency (RF) transmitter. It comprises a hand

held AM transmitter (typically 2-channel), which sends two radio signals for steering and speed

control. The receiver is mounted on the mower portion of the present invention, which receives

the radio frequency signals and convert them into 1.1mSec to 1.8mSec pulses. The width of the

pulse is proportional to the position of the steering and speed transmitter knobs. When the

steering or speed knobs are released, the internal spring would force it to go to a center position

which correlates to a 0 degrees position and 0 mile/hr speed.

Fig. 2 is a representational 3-D Model depicting the typical mechanical and electrical

components of the present invention. On the mower portion of the present invention, one would

find the RF receiver, the controller box designed with novel characteristics, a power control

designed with novel characteristics, rechargeable 12-Volt Batteries (typically 2 seal lead/acid), a

steering control designed with novel characteristics, a motor for speed, a differential, a power

lawn mover engine with blade(s), and an alternator to generate electricity and charge the

batteries.

Fig. 2b is a representational 3-D Model depicting the typical mechanical and electrical

components of an alternate configuration of the present invention. On the mower portion of the

present invention, one would find the RF receiver, the controller box designed with novel

characteristics, a power control designed with novel characteristics, rechargeable 12-Volt

Batteries (typically 2 seal lead/acid), two independent rear motors with speed control, a power

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lawn mover engine with blade(s), and an alternator to generate electricity and charge the

batteries.

Operation

The RF Portion:

The RF Transmitter sends two RF signals which are proportional to the position of the

steering and speed control knobs. The RF receiver picks up the signals and converts the RF

signal into electrical pulses. Table-1 illustrates the electrical pulses.

Table-1

19 mSec Period

1.8 mSec

1.1 mSec

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The Controller Box Portion:

The electrical pulses are connected to a micro controller (e.g., PIC16F73 shown on Fig.

3) which converts the electrical pulses into two 8-bit byte binary values one for the steering

control and speed control. Fig. 3 illustrates a schematic representation of an example of its

functional components. In the depiction, there are two digital to analog converters which

converts the 8-bit binary value into a voltage raging from 0 to 5 volts DC. Table-2 shows the

pulse, binary, voltage, position and speed relation ships.

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Table-2

RF Receiver Electrical Pulse (m Sec)

Micro Controller Pulse to Decimal value 8-bit Byte conversion

Digital to Analog Conversion (Volts)

Position (degrees)

Speed (Miles/hr.) Negative = reverse

1.10 0 0.000 -30 -12 1.20 32 0.625 -22 -9 1.30 64 1.250 -15 -6 1.40 96 1.875 -7 -3 1.50 128 2.500 0 0 1.60 160 3.125 7 3 1.70 192 3.750 15 6 1.80 224 4.375 22 9 1.90 256 5.000 30 12

The microcontroller has connections to a gyro, and its function is to maintain the lawn

follow a straight course whenever the steering command is at 0 degrees (go straight) and the

speed command is greater than 0 mile/hr. Whenever these conditions are met the microcontroller

would remember the initial direction and if the lawn mover deviates from its course, then the

gyro would measure the deviation and the microcontroller would try to corrected by sending the

correct signal to the steering control box.

The Steering Control Box Portion

The steering control box is a close loop feedback control system that uses a potentiometer

to measure the actual position of the wheels. The potentiometer was designed to reduce cost and

accessibility. The actual position measurement is compared to the desire measurement; any

deviations are multiplied by a gain of 2, and sent back to the steering DC Motor. Fig. 4

illustrates a typical example of a feedback control system for the steering motor. Fig. 5

illustrates an example of a placement of the potentiometer, steering motor, and gear box.

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The steering motor is connected to a gear box, the gear box is attached to a plate. The

shaft of the gear box is attached to an arm. The arm moves the tie rod links that would move the

wheels and the potentiometer; hence allowing the potentiometer to send the actual wheel

measurement position.

Fig. 2b illustrates an alternate configuration for the steering control. The invention has

two independent motors with speed control connected to each wheel on the rear. The mover

turns to the right when there is more current flowing through the motor on the left. The mover

turns to the left when there is more current flowing through the motor on the right. This

configuration delivers small turning radios and better terrain adaptation.

The Speed Control Box Portion

The Speed control box is a close loop feedback control system that uses a tachometer

attached the speed motor to measure the actual speed of the lawn mover. The actual speed

measurement is compared to the desire measurement; compare any differences, and sends back

the correct voltage to the speed DC Motor. Fig. 6 illustrates an example of the feedback control

system for the speed control. Fig. 7 illustrates typical components of the Speed motor, gear box,

and differential. The 12VDC speed motor is attached to a gearbox, a tachometer, and the whole

unit is attached to the differential.

The Charging System Portion

The charging systems comprises an alternator attached to the lawn mover metal body.

The gas engine is the prime mover for the alternator. The alternator will generate enough

electricity to power the Controller box, RF receiver, and charge the batteries. Fig. 8 illustrates an

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example of alternator schematics. The alternator has a pulley on its shaft as well as the engine

shaft, and they are linked by a belt. Fig. 9 illustrates a typical design configuration for the

pulley, shaft and belt design for charging the batteries.

Typical parts comprises the components depicted in the circuit schematic may include the

following:

PIC16F73 Microcontroller 1 OP541 High Power OP Amp 2 DAC0800 Digital to Analog Conv. 2 OP741 Operational Amp 2 CRS04 Gyroscope 1 100Kohm Resistor 4 50Kohm Resistor 4 5Kohm Resistor 10 15pF Capacitor 2 20MHz Crystal 1 0.1uF Capacitor 6 RF Rcvr Futaba RF Receiver 1

A detail schematics showing an example of all electrical and mechanical components is

shown in Fig. 10.

Figs. 11a-11b are pictorial views of the present invention actually built and operable.

It should be understood that the preceding is merely a detailed description of one or more

embodiments of this invention and that numerous changes to the disclosed embodiments can be

made in accordance with the disclosure herein without departing from the spirit and scope of the

invention. The preceding description, therefore, is not meant to limit the scope of the invention.

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Rather, the scope of the invention is to be determined only by the appended claims and their

equivalents.

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ABSTRACT OF THE DISCLOSURE

The present invention has a proportional front steering control, forward/reverse speed

control, a gyro for fast straight line cuts, and a gas engine (typical rating being about 4.5 to 7.5

HP) to cut the grass and charge the batteries. All heavy components such as batteries, gas engine

should be engineered for optimum balanced in all its proportions. The batteries can be charged

from a household outlet or from the gas engine itself when operating; it is a hybrid on its own.

The steering control (the heart of the system) has an excellence fast response; it is a fast, safe,

energy efficient, effortless remote control lawn mover that does not compromise speed or power

to cut the lawn. All these unique features make the present invention a lawn mover that one

controls and enjoys.

P03070006.3778c002.provisional application.doc

Fig. 11a

Fig. 11b