System and Method for Cleaning External Walls of Building

Abstract

This solution is for washing and cleaning the external walls of a building, and adopts a lightweight six axis robotic arm mounted on a mini-gondola hoisted by a pulley system with the controlling motor located within the mini-gondola, while another set of motor located on the pulley system at the roof-top end drives the mini-gondola to traverse laterally on a set of twin-rails on the roof-top of the building. Four vacuum suction cups mounted on the minigondola through linear actuator are used to secure the mini-gondola to the wall. Each linear actuator has three ultrasonic distance sensors that measure and manage the distance between the mini-gondola and the wall to be cleaned. Once the gondola is in position, the robotic arm will be activated to start the cleaning process.

Claims

1. A wall cleaning system for spray cleaning external walls of building, the system comprising: a gondola for hanging on a motor driven pulley system, wherein the gondola operationally traverses along a pair of rails travel along a linear distance for a water spraying process to be carried out; a six-axis robotic arm, coupled with a 3D camera, and a spray nozzle on its end effector, the six-axis robotic arm is seated on the gondola for carrying out water spray cleaning on the external walls; wherein the 3D camera mounted on the robotic arm operationally scans a wall area to be sprayed clean; and a software program adapted for receiving the scanned results from the 3D camera and calculating the trajectory path of the spray cleaning motion for the robotic arm.

2. The system according to claim 1, further comprising a water weight for counter balancing on the motor-driven pulley.

3. The system according to claim 1, further comprising a collection hood covering over the water spray nozzle to collect any water debris and fallouts during the spray cleaning process.

4. The system according to claim 1, wherein the gondola further comprises a pair of façade projection wheel adapted for cushioning impact of the gondola made on the facade of the wall to be cleaned.

5. The system according to claim 1, further comprises an industrial PC (personal computer) located within the gondola, the industrial PC is adapted for controlling the motor-driven pulley system to hoist and lower the gondola to locate the vertical location of the robotic arm.

6. The system according to claim 1, further comprises a controlling motor of the pulley system that hoists and lowers the gondola in parallel to the external wall of the building to be cleaned, wherein the controlling motor is located within the gondola.

7. The system according to claim 5, further comprising: four vacuum suction cups mounted respectively on each linear actuator to secure the gondola to the wall when the robotic arm makes a ‘stop’ for the cleaning process to be conducted; the suction cups are controlled by the industrial PC (personal computer) located within the gondola.

8. The system according to claim 5, wherein the industrial PC is adapted to control a controller located on the roof-top to monitor the water level within a water container.

9. The system according to claim 1, further comprising: three ultrasonic distance sensors mounted on each linear actuator on the gondola to measure the distance between the gondola and the wall that is to be cleaned; wherein the distance measured is fed back to control the distance between the gondola and the wall to be cleaned.

Description

BRIEF DESCRIPTION OF DRAWING

[0012] FIG. 1 illustrates a system in accordance with an embodiment of the present invention.

DESCRIPTION

[0013] FIG. 1 illustrates a mini-gondola in accordance with an embodiment of the present invention. A lightweight six-axis robotic arm (2) is adopted to wash and clean the external walls of a building with a high pressure water spray nozzle (1) mounted on the robotic arm's end-effector to spray the water onto the wall. The robotic arm is mounted on a mini-gondola (10 in Diagram) and hoisted by a pulley system with the controlling motor (9) located within the mini-gondola, while another set of motor located on the pulley system (11) at the roof-top end drives the mini-gondola to traverse laterally on a set of twin-rails on the roof-top of the building. The pulley system raises and lowers the mini-gondola in parallel to the external wall of the building to be cleaned, spraying water onto the wall in a vertical manner from top to bottom, column by column.

[0014] 1. The Lightweight Six-Axis Robotic Arm (2)

[0015] The six-axis robotic arm is to be lightweight, and is coupled with a 3D camera and a spray nozzle (high pressure water spray) on its end effector. The 3D camera mounted on the robotic arm scans the wall area (approximately 1.2 m by 1.2 m) to be cleaned; a software program will then calculate the trajectory of the water spraying motion for the robotic-arm to carrying out the water spraying action.

[0016] The robotic arm is controlled (through a RS422 cable, TCP/IP) by an industrial PC (personal computer) (5) mounted within the mini-gondola.

[0017] 2. Adoption of Mini-Gondola (10)

[0018] A specially designed mini-gondola, hoisted by a motor-driven pulley system with the controlling motor of the pulley system within the mini-gondola, is used to seat/house the robotic arm to carry out the cleaning of the external wall of a building. Four vacuum suction cups (7) mounted on the mini-gondola helps to secure the mini-gondola to the wall when the mini-gondola/robotic arm makes a ‘stop’ for the cleaning process to be conducted. To have further securing of the mini-gondola—prevention of swaying motion—a tow line attached to the mini-gondola is used to secure the mini-gondola to the ground.

[0019] An onboard controller (4) mounted on the mini-gondola manages and controls the distance between the mini-gondola and the wall to be cleaned. The measured distance is fed from the onboard controller to the Industrial PC (personal computer located within the mini-gondola), which then activates the robotic arm to start the cleaning process.

[0020] 3. Motor-Driven Pulley System with Controlling Motor within the Mini-Gondola, and Industrial PC for Roof-Top Controller

[0021] The controlling motor (9) of the pulley system that hoists and lowers the mini-gondola in parallel to the external wall of the building to be cleaned is located within the mini-gondola. An Industrial PC (personal computer) located within the mini-gondola controls this controlling motor, hoisting and lowering the mini-gondola in the vertical height position (y-axis) to locate the position of the robotic arm (seated on the mini-gondola) for the cleaning process to be carried out. The Industrial PC also controls another motor (11) that drives the mini-gondola to travel along the linear distance (x-axis), traversing along a set of twin-rails located on the roof-top of the building. Water weight (12) is used to counter balance the pulley system on the twin-rails.

[0022] 4. The Control (Monitoring of Water Container Level) and Discharge of the Water Sprayed from the Nozzle.

[0023] The water will be sprayed onto the wall with a high pressure water sprayer mounted on the end-effector of the robotic arm. An Industrial PC (personal computer) is used to monitor the water level within the water container (that supplies the water to the water sprayer) to ensure that water availability is maintained.

[0024] 5. The Building Facade Cleaning Sequence

[0025] The cleaning sequence will be from left of the building and moving towards the right as the motor-driven pulley system transverses itself in that direction. The water spray cleaning on the wall will be in a vertical manner from top to bottom, column by column; once each column is being cleaned, the motor-driven pulley system will traverse to the right and make another ‘stop’ to clean the next following column.

[0026] 6. Ground Controller

[0027] Through RS422 or RS485 (long distance serial communication), the industrial PC is also controlled by a remote electronic controller to allow the control of the motor-driven pulley system at the ground level.