Robtic dredger
- 1. 3.4.4 Actuators We used DC motors to actuate the pulleys. With the help of switches. We can Move in both direction of the motors. A total of 3 DC motors are used for operation to Carry out. Two DC motors are fitted at the bottom side of slider mechanism use to actuate Pulley. Motor-1 One motor is used for opening and closing of the grab. Opening and closing of Grab mechanism is to collect the sludge in scoops and remove it to hull boats. Motor-2 Another motor is used for vertical motion of the grab assembly. It lifts the scoops From water surface in upward direction and vice versa. Also collecting grab in hull boats. Motor-3 Third motor is for the horizontal motion of the slider assembly by belt and pulley Mechanism. First motor should be operated during the vertical motion of grab assembly Simultaneously with the second motor. An attempt is made to show all the motors in one Fig. We used a battery to run DC motors. 3.4.5 Two Hull Boats We aimed in placing the grab mechanism in the middle of the boat such that the Stability of the boat won’t be affected during operation. For this purpose, we proposed to Have two hull connected with some gap in between for the grab mechanism. These hulls Are made up of plastic. The main aim to use of hull boat is stability increases and boats Can’t be wobble during operation. Both boats are connected by using frame. Frame is Made up of m.s.material L-shaped rod. Actual slider mechanism is directly placed on the
- 2. Frame. Due to frame and two hull boats assembly as shown in figure stability of hull Boats increased to large extent. We connected the two hulls using aluminium rods so that One of the two hulls won’t wobble during the operation. The two hulls connected with Aluminium rods are shown in figure. For extra stability of the system, we fixed a fixed a firm mild steel frame on the two hull boats as shown in figure. Mild steel frame is painted after a coating with varnish to prevent it from rusting. 3.5 DESIGN CALCULATIONS 3.5.1 Grab mechanism We used simple grabbing mechanism for grab the sludge using pulleys and string. Design of scoops: Design procedure for scoops is as follows Weight of material lifted by scoops: Scoops is nothing but elliptical tank or cylinder. Volume=𝐴 = 𝜋AB1 = π *11*12.5*1 = 5612.75 cm3
- 3. =5.612 litre Total mass of water Hyacinths carrying by scoops: Density of water hyacinth = 260 kg/m3 = 0.26 kg/litre Mass = 5.612 * 0.26 = 1.45 kg Scoope can carry 1.45 kg mass of water hyacinths at time Weight of scoope: Elliptical Area = πab = π * 12.5 * 11 = 431.96 cm2 Volume = Elliptical Area * thickness = 431.96 * 0.1 = 43.196 cm3 Rectangular area = length * width = 5 * 7 = 35 cm2 Volume = 3.5 cm3 Curve area = 27 * 13 = 351 cm3 Volume = 35.1 cm3 Total volume = 2 * (43.196+3.5+35.1) = 941.12 cm3
- 4. Weight of scoops = volume * density = 941.12 * 7.860 * 1 = 1286.81 gm. Force Analysis of Link Overall mass of scoops = 1.3 kg Force required to apply by each link to open the scoops = 1.3 * 9.81 /2 = 6.37 N Shear force calculation: Bending moment calculation: B.M. at B = 0
- 5. B .M. at A = 6.37 * 0.23 = 1.54 N-m Dimension of link: 3.5.2 Selection of string Tension on string in grabbing Mechanism Tension on each string = 6.30 N Dimension of string used Diameter of string = 1 mm Cross sectional area of string = π/4 * d2 = 0.785 mm2
- 6. Maximum Load Lift by the string = 49 N (5 kg) Tensile strength of string = 49/0.785 = 62.42 N/mm2 Introducing Factor of safety = 3 Tensile strength = 62.42/3 = 20.80 N/mm2 Actual Tensile stress on each string = T/A = 6.30/0.785 = 8.02 N/mm2 Since tensile stress is less than tensile strength of string. 8.02 < 20.80 ………Hence String is safe. 3.5.3 Tension in string in Lifting Mechanism Total weight carried by string = 26.84 N Total weight carried by each string = 13.42 N = 13.42/0.785 = 17.09 N/mm2 Tensile strength = 20.80 N/mm2 Since tensile stress is less than tensile strength of string. 17.09 < 20.80 Hence string is safe. 3.5.4 Motor selection Motor used for grabbing and lifting mechanism Total weight which has to lift by the motor =
- 7. Weight of water hyacinth +weight of scope = 26.84 N No. of motors = 2 Weight on each motors = 13.42 N Diameter of pulley = 1 cm Torque = tension in spring * radius of pulley Tension in string = 13.42 N = 1.36 kg Torque = 1.36 * 0.5 = 0.6838kg-cm Specification of motors Type: DC gear motor Voltage: 12 volt Speed: 10 rpm Torque: 6 kg-cm (0.588 N-m) 3.5.5 Motor, pulley and Belt for sliding mechanism: Total Load = total load hang by slider + weight of motor used = 2.72 + 2 + (2 * 125) = 2.72 + 0.25 = 3 kg Specification of motors: Type: DC motor Voltage: 12 volt Speed: 50 rpm
- 8. Torque: 1.4 kg-cm Specification of pulley: Dimension of pulley: We used two pulley for sliding mechanism one at the motor shaft and another at end of frame. Pulley Length of belt Belt is fitted on pulley. It is made of leather of 4 mm diameter. Length of belt = 2 * distance between two pulleys + π d = 2 * (58+ 58+35) + 3.14 = 305.14 cm 3.5.6 Designof Hulls Dimension of hulls, Height = 85 cm Radius = 29 cm Volume = ½ * π * 292 * 85
- 9. = 112231.45 cm2 Total volume of two Hulls = plastic 3.5.7 Dimension of frame 1. Base frame = 153 * 92 2. Vertical Frame = 153 * 66.5 Material for Frame = mild steel 3.6 System Manufacturing Fabrication is a process of making components by cutting, bending and Assembling. Fabrication is the extended phase in our project. After completing design of the machine. We are in the process of doing fabrication and we will continue it in the further semester. After designing all the components and selection of safety and measuring instruments the next step is to fabrication work of the project. Fabrication work is done at- ‘Sai’ Workshop Yeola, dist-Nashik 3.6.1 Frame Material required a. L-size c/s frame of the size 0.5” * 0.5” and length 153 cm (4 nos).
- 10. b. L-size c/s frame of the size 0.5” * 0.5” and length 66.5 cm (4 nos). c. L-size c/s frame of the size 0.5” * 0.5” and length 92 cm (4 nos). d. L-size c/s frame of the size 0.5” * 0.5” and length 153 cm (4 nos). Step followed to manufacture the frame a. At first we are taken raw size L-size mild steel bar and cut them into above required size by using cutter. b. Then we finish the cutting edges by grinder and files. c. Then we join the all angle frame to each other one by one using the welding machine. We join this skeleton of the frame according to drawing means in the prescribed fashion. d. Join all part of the frame with help of welding machine after above welded part smooth grinder done. e. Here the manufacturing of frame is completed. Process sheet of frame Table 1 process sheet for main frame Sr.no Operation description Machine used Tool used Assembly with Time in min. 1 marking scale By hand - 15 2 cutting Cutting machine Grinder cutter - 15 3 Welding Arc welding - Assembly with frame 20 3.6.2 Scoops
- 11. Material required a. Sheet metal of size 50 cm * 30 cm Steps followed to manufacture the scoops a. At first we take metal sheet of size 50 * 30 cm as raw material. b. Cut them into required size by cutter c. Marking is done as per the design on raw material and then cut the sheet metal. d. Then we finish cutting edges by grinder and files. e. Then for fitting of scoops into metal box drill is made at parts of scoops f. Then we cut two parts of size 27 * 13 cm to joining of scoop g. Then we join all parts as per design by welding process by using welding machine h. We used electric arc welding machine for this process. i. After that finishing is done by smooth grinding machine. j. Here the manufacturing of scoops is completed Process sheet of scoops Table 2 process sheet for scoops Sr.no Operation description Machine used Tool used Assembly with Time in min. 1 marking scale By hand - 15 2 cutting Cutting machine Grinder cutter - 15 3 Welding Arc welding - Assembly with frame 20 4 finishing Grinder Grnder 15 3.6.3 Links Material Required a. Rectangular shape MS solid rod of 1cm * 2 mm of length 23 cm(4 nos). b. Rectangular shape MS solid sheet of size 19cm * 7.5cm(1 nos). c. Rectangular shape MS solid sheet of size 10cm * 6cm(1 nos). d. Rectangular shape MS solid sheet of size 10cm * 2cm(2 nos). e. Rectangular shape MS solid sheet of size 6cm * 2cm(1 nos).
- 12. Steps followed to manufacturing the Link a. First from raw material cut 2 rods b. Two metal strips of size are made champer at ends. c. For connecting links and surface chamfer and given the circular shape by grinder. d. For link 2 metal is cut in rectangular shape of size 1 * b and cut the centre position e. Grind finishing is done by using grinder. f. As per the design metal strips are cut for manufacturing of link 2. These are joined. g. Electric arc welding. h. After this finishing is done by grinder machine for both link 2 and link 3.Process sheet of links Table 3 proceses sheet for links Sr.no Operation description Machine used Tool used Assembly with Time in min. 1 marking scale By hand - 15 2 Cutting Cutting machine Grinder cutter - 15 3 Welding Arc welding - Assembly with frame 20 3.6.4 Slider Material required a. Rectangular c/s aluminium hollow bar of size 4cm * 1.8 cm of length 26 cm (3 nos). b. Rectangular c/s aluminium hollow bar of size 4cm * 1.8 cm of length 25 cm (3 nos). Steps followed to manufacture the slider a. At first we take rectangular c/s aluminium hollow bar of size 4cm*1.8cm.
- 13. b. Three parts of same size cut by cutter. c. Two parts of size cut by cutter d. Then rectangular shape is formed from cut section of aluminium bar by using screw. e. Ygjuhkhkj f. From the bottom side using pulleys are fixed as per design by using screws. g. Two motors are also fixed at opposite sides’ rectangular frame formed by using screws and L-shaped rods. h. Here the manufacturing of slider is completed. ,