ROBO VACCUUM CLEANER

By

ABSTRACT:

Robotics is an emerging field of development in the 21st century, people all over the world are investing time and money in the development and improvement of robotics technologies. They make different robots to perform specific tasks. Robots are now widely used in car manufacturing industries, in those areas where extreme accuracy is required and human hands are insufficient for the task.

PROBLEM:

The problems that are faced in the basic requirement of robotic expertise, is to figure out the governing phenomenon for which the robot is to be built. And then the extent of robotic power to be impolite is calculated.

Now the problem is to build a rob vacuum that could sit beside the carpeted room and have sufficient sensors that could readily detect any dirt or spill over on the carpet and then it travels to the spot and clean.

CALCULATIONS:

A vacuum cleaner creates a vacuum that causes the brush of vacuum forcibly stick to the carpet then to move the brush over the carpet extra force is requires to be applied.

Governing equations to get to the form:

F applied−f s=ma eq. 1

A vacuum is the deficiency of air in a certain volume within high pressure region, this phenomenon let a very unique thing to happen which was first demonstrated by Archimedes that is the hemisphere vacuum experiment which demonstrate the load applied by the atmospheric air on the hemisphere that is the to separate the two hemisphere is very difficult.

In vacuum cleaners although vacuum is low therefore low vertical down force is experienced on the brush:

VOLUMETRIC FLOW:

Flow rate may be calculated from

Q=K1Ao√ 2 ∆ Pρ

WhereQ – Volumetric flow rateK1 – flow coefficientAo – area of the orifice plateΔP – pressure difference across the orifice plateρ - Air density

1

Volume of brush cavity: V=l*b*h

The air pressure of atmospheric air is:

Patm =101 kPa

Pressure force over that area of vacuum :

W=Patm/Ao

Now, the reaction of surface: R=W fs=µR

Eq. 1 F applied−µ R=ma

and then the robot can manage the speed and power to be diploid to clean the place.

CONCLUSION:

This type of problems are readily observer in robotics as this field is emerging very fast and we can have very quick solution to the problems faced in this regard and can come up with latest technologies that can change the world.

2

REFFERENCE:

ME 322: Vacuum Cleaner Performance Test

OBJECTIVES

The objective of this laboratory is to measure the performance of two vacuum cleaner designs. Performance will be characterized based on the suction that each vacuum develops under varying load conditions. The procedure for testing is based on an ASTM standard [1].

BACKGROUND

The idea of a vacuum cleaner originated in the 19th century. The first vacuum cleaners had to be operated manually. Two persons were needed for this: one to operate the bellows and the other to move the mouthpiece over the floor. The dust was blown into the air, similar to sweeping with a broom. In 1901 Hubert Booth changed the idea into something more useful, when Booth came up with the idea of sucking the dust off the floor, and subsequently filtering it out of the air stream. The process whereby particles are suspended in a high velocity air stream for the purpose of moving the particles from one place to another is called pneumatic transport. All modern vacuum cleaners are based on Booth's principle, that of transporting the dust and dirt in a high velocity air stream, and then collecting the dust through a filtering process.

HOW A VACUUM CLEANER MOVES DIRT

Have you ever used a leaf blower or watched one in action? The blower moves debris through the action of moving air – the movement of the air causes an aerodynamic drag force that pulls the debris along with the air. This drag force increases with higher wind speeds and, hence, can move heavier objects at these higher speeds. This action of moving a solid object by entraining it in moving air is known as "pneumatic transport." Pneumatic transport is widely used in industry to move solid particles from one point to another. It is how they get the wheat flour into the bags you buy at the store, or the cereal in the box. It is also how a vacuum cleaner moves dirt.

3

As air moves past a solid object, a drag force results. This force is proportional to the square of the velocity times the frontal area of the solid. If the force is high enough to overcome the static frictional and gravity forces that hold the object in place, the object will move and, if the drag force is greater still, the object will become suspended (entrained) in the air and move with the air.

A vacuum cleaner operates using this principle of pneumatic transport. The objective is to move dirt from the floor or furniture to a collection bag within the vacuum cleaner. To do this, the vacuum cleaner moves air and entrained dirt through itself. It contains a blower, a cleaning nozzle, connecting tubes, and a breathable collection filter bag (or in some designs a collection chamber). Because it uses pneumatic transport principles, the more air the vacuum moves the better its performance. So one goal in designing a vacuum cleaner is to generate airflow. A key to this end is the design of the blower and connecting tubes.

Vacuum Cleaner Design

A blower is used to move the air in a vacuum cleaner. Typically, a centrifugal (often called radial) blower is used (see Figure 1 below), which is turned by an electric motor. In such a blower, a rotating impeller will bring about a pressure difference: low pressure or suction at the inlet end and high pressure at the exit. The pressure difference causes air to move. The higher this pressure difference, the higher the air flow rate. Fluid enters the blower along its centerline parallel to the rotational axis. It is turned 90o within the impeller to exit flowing radially outwards through its volute and diffuser. The impeller (Figures 1 and 2) contains blades that act as small wings to create the pressure difference. Generally, the more blades, the higher the pressure difference that a particular blower can generate and the lower noise it produces. The impeller is enclosed within a casing. The closer the fit between the impeller and the casing, the higher the pressure and flow rate.

The nozzle is designed to create a high airflow near the surface being cleaned to allow dirt to be swept up by the moving air and entrained into the vacuum cleaner. A rotating beater bar is often used to beat the carpet to stir up trapped dust and to sweep up larger debris. Once stirred, the dust is entrained by the moving air.

Connecting tubing becomes the vessel for pneumatic transport of dirt within the vacuum cleaner. The connecting tubing connects the nozzle to the blower or the cleaning tools to the blower. Some tubing may be visible on the outside of the vacuum cleaner, but there are also tubing passages internal to the device, as well. The tubing design is very important. Short, large diameter tubing is preferred over long and/or small diameter

4

tubing. This is because flow resistance in a tube is proportional to the tube length and is inversely proportional to the tube diameter to the fifth power (flow losses ∝ L/d5)! So the distance from the nozzle to the blower is preferably short and spacious. It is common to find connecting tubing as small in diameter as 1.25 inches, which is okay for short runs, but 2 inch diameter or more are preferred to maintain higher flow rates.

Figure 1. Cut-away View of Centrifugal Blower (also known as a Radial Blower).

5

Figure 2 Cut-away views of a typical impeller used in a centrifugal blower.

Vacuum Cleaner Performance

Typical blower-system performance curves for several vacuum cleaners are shown in Figure 3. These are plotted as “pressure” or static (suction) head versus “air flow rate”. The static head tends to be high at low flow rates and falls to zero at the maximum flow rate. The blower will actually operate at the point on the curve where the blower curve matches the system flow resistance pressure. Normal operating condition is somewhere in the middle of the curve but varies with the specific cleaning chore (plush carpets impart a higher pressure resistance then bare wood floors, etc.). The vast majority of vacuum cleaners today do not utilize a speed controller on the blower. This means that the blower rotating speed changes with cleaning chore. The more air that flows through the blower, the slower it turns. A typical blower turns at 30,000 down to 20,000 RPM and can vary by ± 8,000 RPM during normal cleaning chores.

6

Figure 3. Typical Flow Curves for Commercial Vacuum Cleaners

Lets think about the blower curves in Figure 3: If you block the end of the nozzle, the flow falls to zero – the static head is highest (hence, high suction and referred to as the seal suction). The RPM rises since there is no air flow load on the impeller. As you vacuum a carpet, the nozzle is partially blocked – this is normal loading and somewhere in the middle of the curves. In fact, the low plush carpet condition is labeled with a ‘star’. The RPM is somewhere near its designed operating value so it is likely to give its best performance here. If you place nozzle in the open air, the only blockage is the losses in the vacuum lines giving maximum flow rate at lowest suction and lowest RPM. The best cleaning vacuum cleaner will tend to have higher suction at higher flow rates because this gives best pneumatic conveying capability. In fact, the product of static head and flow rate is a measure of cleaning capability. The differences in the curves shown reflect design differences in the different devices. All of these units have very good cleaning performance.

The concept of seal suction brings up an interesting pet peeve of this author. A typical sales pitch is to feel the suction of a vacuum cleaner when it is totally blocked. The salesperson has you place your hand over the end or something similar: Strong

7

suction yet no air movement – hence, no pneumatic transport and no cleaning. So this test tells little about how well a particular vacuum will clean. A better test is to know air flow rate under a partial blockage. Seal suction is useful, but remember air flow is what it takes to clean!

PROCEDURE

You are to measure the performance of two models of vacuum cleaner. The test is based on ASTM F 588-03. A plenum is an essential part of this test standard; such a plenum is provided in the lab. The test procedure is outlined below.

1. Measure the barometric pressure and the air temperature in the room where the test will be conducted.

2. Connect the vacuum cleaner to the appropriate inlet on the plenum.

3. Familiarize yourself with the current measuring instrumentation, and the manometer that will measure the suction.

4. Ensure that the hose is free of kinks or abrupt bends.

5. There is a location for installation of various sized orifice plates in the top of the plenum. Remove any orifice plate from this location. We will refer to this as an “open orifice” condition.

6. Run the vacuum cleaner under the “open orifice” condition for two minutes to allow the motor to reach its operating temperature.

7. Install the 2 inch orifice plate, with the vacuum continuing to run.

8. Wait 1 minute and record the suction and the current.

9. Remove the 2 inch orifice and allow the vacuum to run for 1 minute at open orifice condition.

10. Repeat these measurements for the 1.5, 1, 0.75, 0.5, 0.25 and 0 inch orifice plates.

11. Repeat these measurements for the other vacuum cleaner.

DATA ANALYSIS

8

You are to calculate the volumetric flow rate of air from the measured values of suction for each of the orifices. Flow rate measurement using an orifice is discussed in section

10.5 of the text. The flow rate may be calculated from

Q KA= 1 o 2ρ∆P

where

Q – volumetric flow rate

K1 – flow coefficient

Ao – area of the orifice plate

∆P – pressure difference across the orifice plate ρ - air density

The value of K1 has been determined through extensive testing by ASTM. This is the purpose of providing a standard plenum design. The values of K1 are provided in Table 1. Carefully note the definitions and units of the various quantities.

Fluid power is a concept that allows the direct measure of the rate at which work is being done on a fluid. The fluid power can be expressed

P= ∆Q P

Deliverables

1. A plot of suction as a function of flow rate for each of the vacuums.

2. A plot of the fluid power as a function of suction for each of the vacuum.

9

3. A plot of efficiency as a function of fluid power, where efficiency is the ratio of fluid power to electric power.

4. A discussion of the results in terms of cleaning performance of the vacuum cleaners.

10

11

12